Acoustic output apparatus and method thereof

ABSTRACT

The present disclosure relates to an acoustic output apparatus. The acoustic output apparatus may include an earphone core including at least one acoustic driver for outputting sound though one or more sound guiding holes set on the acoustic output apparatus, a controller configured to cause the at least one acoustic driver to output sound, a power source assembly configured to provide electrical power to the earphone core, the one or more sensors, and the controller, and an interactive control component configured to allow an interaction between a user and the acoustic output apparatus.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of International Application No.PCT/CN2020/087002, filed on Apr. 26, 2020, which claims priority toChinese Patent Application No. 201910888067.6, filed on Sep. 19, 2019,Chinese Patent Application No. 201910888762.2, filed on Sep. 19, 2019,and Chinese Patent Application No. 201910364346.2, filed on Apr. 30,2019, the contents of each of which are hereby incorporated byreference.

TECHNICAL FIELD

The present disclosure generally relates to acoustic devices, and moreparticularly, relates to a smart wearable apparatus and method foracoustic output.

BACKGROUND

With the development of acoustic technology, acoustic output apparatushave been widely used. An open binaural acoustic output apparatus is aportable audio apparatus that facilitates sound conduction within aspecific range of a user. In this case, the user may hear sound inambient environment when the acoustic output apparatus delivers sound(e.g., a piece of music, a news broadcast, a weather forecast, etc.) tothe user. However, an open structure of the open binaural acousticoutput apparatus may also lead to a sound leakage of a certain extent.Therefore, it is desirable to provide an acoustic output apparatusand/or method for reducing sound leakage and enhancing sound deliveredto the user, thereby improving an audio experience of the user.

SUMMARY

An aspect of the present disclosure relates to an acoustic outputapparatus. The acoustic output apparatus may include an earphone coreincluding at least one acoustic driver for outputting sound though oneor more sound guiding holes set on the acoustic output apparatus. Theacoustic output apparatus may further include a controller configured tocause the at least one acoustic driver to output sound. The acousticoutput apparatus may further include a power source assembly configuredto provide electrical power to the earphone core, the one or moresensors, and the controller. And the acoustic output apparatus may alsoinclude an interactive control component configured to allow aninteraction between a user and the acoustic output apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an exemplary acoustic outputapparatus embodied as a glasses according to some embodiments of thepresent disclosure;

FIG. 2 is a schematic diagram illustrating exemplary components in anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 3 is a block diagram illustrating an exemplary interactive controlcomponent in an acoustic output apparatus according to some embodimentsof the present disclosure;

FIG. 4 is a block diagram illustrating an exemplary voice control modulein an acoustic output apparatus according to some embodiments of thepresent disclosure;

FIG. 5 is a schematic diagram illustrating exemplary two point sourcesaccording to some embodiments of the present disclosure;

FIG. 6 is a schematic diagram illustrating a variation of sound leakageof two point sources and a single point source along with frequencyaccording to some embodiments of the present disclosure;

FIGS. 7A-7B are graphs illustrating a volume of the near-field sound anda volume of the far-field leakage as a function of a distance of twopoint sources according to some embodiments of the present disclosure;

FIG. 8 is a schematic diagram illustrating an exemplary acoustic outputapparatus according to some embodiments of the present disclosure;

FIGS. 9A-9B are schematic diagrams illustrating exemplary applicationscenarios of an acoustic driver according to some embodiments of thepresent disclosure;

FIGS. 10A-10C are schematic diagrams illustrating exemplary soundoutputs according to some embodiments of the present disclosure;

FIGS. 11A-11B are schematic diagrams illustrating acoustic outputapparatuses according to some embodiments of the present disclosure;

FIGS. 12A-12C are schematic diagrams illustrating acoustic routesaccording to some embodiments of the present disclosure;

FIG. 13 is an exemplary graph illustrating a sound leakage under acombination of two sets of two point sources according to someembodiments of the present disclosure;

FIG. 14 is a schematic diagram illustrating another exemplary acousticoutput apparatus according to some embodiments of the presentdisclosure;

FIG. 15 is a schematic diagram illustrating two point sources andlistening positions according to some embodiments of the presentdisclosure

FIG. 16 is a graph illustrating a variation of a volume of the soundheard by the user of a two point sources with different distances as afunction of frequency according to some embodiments of the presentdisclosure;

FIG. 17 is a graph illustrating a variation of a normalized parameter oftwo point sources in a far field along with frequency according to someembodiments of the present disclosure;

FIG. 18 is a distribution diagram illustrating an exemplary baffleprovided between two point sources according to some embodiments of thepresent disclosure;

FIG. 19 is a graph illustrating a variation of a volume of sound heardby the user as a function of frequency when an auricle is locatedbetween two point sources according to some embodiments of the presentdisclosure;

FIG. 20 is a graph illustrating a variation of a volume of leaked soundas a function of frequency when an auricle is located between two pointsources according to some embodiments of the present disclosure;

FIG. 21 is a graph illustrating a variation of a normalized parameter asa function of frequency when two point sources of an acoustic outputapparatus is distributed on both sides of an auricle according to someembodiments of the present disclosure;

FIG. 22 is a graph illustrating a variation of a volume of sound heardby the user and a volume of leaked sound as a function of frequency withand without a baffle between two point sources according to someembodiments of the present disclosure;

FIG. 23 is a graph illustrating a variation of a volume of sound heardby the user and a volume of leaked sound as a function of distancebetween two point sources at a frequency of 300 Hz and with or without abaffle according to some embodiments of the present disclosure;

FIG. 24 is a graph illustrating a variation of a volume of sound heardby the user and a volume of leaked sound as a function of distancebetween two point sources at a frequency of 1000 Hz and with or withouta baffle according to some embodiments of the present disclosure;

FIG. 25 is a graph illustrating a variation of a volume of sound heardby the user and a volume of leaked sound as a function of distance at afrequency of 5000 Hz and with or without a baffle between the two pointsources according to some embodiments of the present disclosure;

FIGS. 26-28 are graphs illustrating a variation of a volume of soundheard by the user as a function of frequency when a distance d of twopoint sources is 1 cm, 2 cm, 3 cm, respectively, according to someembodiments of the present disclosure;

FIG. 29 is a graph illustrating a variation of a normalized parameter asa function of frequency when a distance d of two point sources is 1 cmaccording to some embodiments of the present disclosure;

FIG. 30 is a graph illustrating a variation of a normalized parameter asa function of frequency when a distance d of two point sources is 2 cmaccording to some embodiments of the present disclosure;

FIG. 31 is a graph illustrating a variation of a normalized parameter asa function of frequency when a distance d of two point sources is 4 cmaccording to some embodiments of the present disclosure;

FIG. 32 is a graph illustrating exemplary distributions of differentlistening positions according to some embodiments of the presentdisclosure;

FIG. 33 is a graph illustrating a volume of sound heard by the user froma two point sources without baffle at different listening positions in anear field as a function of frequency according to some embodiments ofthe present disclosure;

FIG. 34 is a graph illustrating a normalized parameter of two pointsources without baffle at different listening positions in a near fieldaccording to some embodiments of the present disclosure;

FIG. 35 is a graph illustrating a volume of sound heard by the user fromtwo point sources with a baffle at different listening positions in anear field as a function of frequency according to some embodiments ofthe present disclosure;

FIG. 36 is a graph illustrating a normalized parameter of two pointsources with a baffle at different listening positions in a near fieldaccording to some embodiments of the present disclosure;

FIG. 37 is a schematic diagram illustrating two point sources and abaffle according to some embodiments of the present disclosure;

FIG. 38 is a graph illustrating a variation of a volume of thenear-field sound as a function of frequency when a baffle is atdifferent positions according to some embodiments of the presentdisclosure;

FIG. 39 is a graph illustrating a variation of a volume of the far-fieldleakage as a function of frequency when a baffle is at differentpositions according to some embodiments of the present disclosure;

FIG. 40 is a graph illustrating a variation of a normalization parameteras a function of frequency when a baffle is at different positionsaccording to some embodiments of the present disclosure;

FIG. 41 is a schematic diagram illustrating another exemplary acousticoutput apparatus according to some embodiments of the presentdisclosure;

FIG. 42 is a schematic diagram illustrating an exemplary acoustic outputapparatus customized for augmented reality according to some embodimentsof the present disclosure;

FIG. 43 is a flowchart illustrating an exemplary process for replayingan audio message according to some embodiments of the presentdisclosure;

FIG. 44 is a schematic diagram illustrating an exemplary acoustic outputapparatus focusing on sounds in a certain direction according to someembodiments of the present disclosure; and

FIG. 45 is a schematic diagram illustrating an exemplary user interfaceof an acoustic output apparatus according to some embodiments of thepresent disclosure.

DETAILED DESCRIPTION

In order to illustrate the technical solutions related to theembodiments of the present disclosure, brief introduction of thedrawings referred to in the description of the embodiments is providedbelow. Obviously, drawings described below are only some examples orembodiments of the present disclosure. Those having ordinary skills inthe art, without further creative efforts, may apply the presentdisclosure to other similar scenarios according to these drawings.Unless stated otherwise or obvious from the context, the same referencenumeral in the drawings refers to the same structure and operation.

An acoustic output apparatus in the present disclosure may refer to adevice having a sound output function. In practical applications, theacoustic output apparatus may be implemented by products of varioustypes, such as bracelets, glasses, helmets, watches, clothings, orbackpacks. For illustration purposes, a glasses with a sound outputfunction may be provided as an example of the acoustic output apparatus.Exemplary glasses may include myopia glasses, sports glasses, hyperopiaglasses, reading glasses, astigmatism lenses, wind/sand-proof glasses,sunglasses, ultraviolet-proof glasses, welding mirrors, infrared-proofmirrors, and virtual reality (VR) glasses, augmented Reality (AR)glasses, mixed reality (MR) glasses, mediated reality glasses, or thelike, or any combination thereof.

FIG. 1 is a schematic diagram illustrating an exemplary acoustic outputapparatus embodied as a glasses according to some embodiments of thepresent disclosure. As shown in FIG. 1, a glasses 100 may include aframe and lenses 140. The frame may include legs 110 and 120, a lensring 130, a nose pad 150, or the like. The legs 110 and 120 may be usedto support the lens ring 130 and the lenses 140, and fix the glasses 100on the user's face. The lens ring 130 may be used to support the lenses140. The nose pad 150 may be used to fix the glasses 100 on the user'snose.

The glasses 100 may be provided with a plurality of components which mayimplement different functions. Exemplary components may include a powersource assembly for providing power, an acoustic driver for generatingsound, a microphone for detecting external sound, a bluetooth module forconnecting the glasses 100 to other devices, a controller forcontrolling the operation of other components, or the like, or anycombination thereof. In some embodiments, the interior of the leg 110and/or the leg 120 may be provided as a hollow structure foraccommodating the one or more components.

The glasses 100 may be provided with a plurality of hollow structures.For example, as shown in FIG. 1, a side of the leg 110 and/or the leg120 facing away from the user's face may be provided with sound guidingholes 111. The sound guiding holes 111 may be connected to one or moreacoustic drivers that are set inside of the glasses 100 to export soundproduced by the one or more the acoustic drivers. In some embodiments,the sound guiding holes 111 may be provided at a position near theuser's ear on the leg 110 and/or the leg 120. For example, the soundguiding holes 111 may be provided at a rear end of the leg 110 and/orthe leg 120 being far away from the lens ring 130, a bending part 160 ofthe leg, or the like. As another example, the glasses 100 may also havea power interface 112, which may be used to charge the power sourceassembly in the glasses 100. The power interface 112 may be provided ona side of the leg 110 and/or the leg 120 facing the user's face.Exemplary power interfaces may include a dock charging interface, a DCcharging interface, a USB charging interface, a lightning charginginterface, a wireless charging interface, a magnetic charging interface,or the like, or any combination thereof. In some embodiments, one ormore sound inlet holes 113 may also be provided on the glasses 100, andmay be used to transmit external sounds (for example, a user's voice,ambient sound, etc.) to the microphones in the glasses 100. The soundinlet holes 113 may be provided at a position facilitating anacquisition of the user's voice on the glasses 100, for example, aposition near the user's mouth on the leg 110 and/or 120, a positionnear the user's mouth under the lens ring 130, a position on the nosepad 150, or any combination thereof. In some embodiments, shapes, sizes,and counts of the one or more hollow structures on the glasses 100 mayvary according to actual needs. For example, the shapes of the hollowstructures may include, but not limited to, a square shape, a rectangleshape, a triangle shape, a polygon shape, a circle shape, an ellipseshape, an irregular shape, or the like.

In some embodiments, the glasses 100 may be further provided with one ormore button structures, which may be used to implement interactionsbetween the user and the glasses 100. As shown in FIG. 1, the one ormore button structures may include a power button 121, a soundadjustment button 122, a playback control button 123, a bluetooth button124, or the like. The power button 121 may include a power on button, apower off button, a power hibernation button, or the like, or anycombination thereof. The sound adjustment button 122 may include a soundincrease button, a sound decrease button, or the like, or anycombination thereof. The playback control button 123 may include aplayback button, a pause button, a resume playback button, a callplayback button, a call drop button, a call hold button, or the like, orany combination thereof. The bluetooth button 124 may include abluetooth connection button, a bluetooth off button, a selection button,or the like, or any combination thereof. In some embodiments, the buttonstructures may be provided on the glasses 100. For example, the powerbutton may be provided on the leg 110, the leg 120, or the lens ring130. In some embodiments, the one or more button structures may beprovided in one or more control devices. The glasses 100 may beconnected to the one or more control devices via a wired or wirelessconnection. The control devices may transmit instructions input by theuser to the glasses 100, so as to control the operations of the one ormore components in the glasses 100.

In some embodiments, the glasses 100 may also include one or moreindicators to indicate information of one or more components in theglasses 100. For example, the indicators may be used to indicate a powerstatus, a bluetooth connection status, a playback status, or the like,or any combination thereof. In some embodiments, the indicators mayindicate related information of the components via different indicatingconditions (for example, different colors, different time, etc.). Merelyby way of example, when a power indicator is red, it is indicated thatthe power source assembly may be in a state of low power. When the powerindicator is green, indicating that the power source assembly may be astate of full power. As another example, a bluetooth indicator may flashintermittently, indicating that the bluetooth is connecting to anotherdevice. The bluetooth indicator may be blue, indicating that thebluetooth may be connected successfully.

In some embodiments, a sheath may be provided on the leg 110 and/or theleg 120. The sheath may be made of soft material with a certainelasticity, such as silicone, rubber, etc., so as to provide a bettersense of touch for the user.

In some embodiments, the frame may be formed integrally, or assembled byplugging, inserting, or the like. In some embodiments, materials used tomanufacture the frame may include but not limited to, steel, alloy,plastic, or other single or composite materials. The steel may includebut not limited to, stainless steel, carbon steel, or the like. Thealloy may include but is not limited to, aluminum alloy,chromium-molybdenum steel, rhenium alloy, magnesium alloy, titaniumalloy, magnesium-lithium alloy, nickel alloy, or the like. The plasticmay include but not limited to, acrylonitrile-butadiene-styrenecopolymer (Acrylonitrile butadiene styrene, ABS), polystyrene (PS), highimpact polystyrene (HIPS), polypropylene (PP), polyethyleneterephthalate (PET), polyester (PES), polycarbonate (PC), polyamide(PA), polyvinyl chloride (PVC), polyethylene and blown nylon, or thelike. The single or composite materials may include but not limited to,glass fiber, carbon fiber, boron fiber, graphite fiber, graphene fiber,silicon carbide fiber, aramid fiber and other reinforcing materials; ora composite of other organic and/or inorganic materials, such as glassfiber reinforced unsaturated polyester, various types of glass steelwith epoxy resin or phenolic resin, etc.

The description of the glasses 100 may be provided for illustrationpurposes and not intended to limit the scope of the present disclosure.For those skilled in the art, various changes and modifications may bemade according to the description of the present disclosure. Forexample, the glasses 100 may include one or more cameras to captureenvironmental information (for example, scenes in front of the user). Asanother example, the glasses 100 may also include one or more projectorsfor projecting pictures (for example, pictures that users see throughthe glasses 100) onto a display screen.

FIG. 2 is a schematic diagram illustrating components in an acousticoutput apparatus (e.g., the glasses 100). As shown in FIG. 2, theacoustic output apparatus 200 may include one or more of an earphonecore 210, an auxiliary function module 220, a flexible circuit board230, a power source assembly 240, a controller 250, or the like.

The earphone core 210 may be configured to process signals containingaudio information, and convert the signals into sound signals. The audioinformation may include video or audio files with a specific dataformat, or data or files that may be converted into sound in a specificmanner. The signals containing the audio information may includeelectrical signals, optical signals, magnetic signals, mechanicalsignals or the like, or any combination thereof. The processingoperation may include frequency division, filtering, denoising,amplification, smoothing, or the like, or any combination thereof. Theconversion may involve a coexistence and interconversion of energy ofdifferent types. For example, the electrical signal may be convertedinto mechanical vibrations that generates sound through the earphonecore 210 directly. As another example, the audio information may beincluded in the optical signal, and a specific earphone core mayimplement a process of converting the optical signal into a vibrationsignal. Energy of other types that may coexist and interconvert to eachother during the working process of the earphone core 210 may includethermal energy, magnetic field energy, and so on.

In some embodiments, the earphone core 210 may include one or moreacoustic drivers. The acoustic driver(s) may be used to convertelectrical signals into sound for playback. More details of the acousticdriver(s) may be disclosed elsewhere in the present disclosure, forexample, FIG. 8 and the descriptions thereof.

The auxiliary function module 220 may be configured to receive auxiliarysignals and execute auxiliary functions. The auxiliary function module220 may include one or more microphones, key switches, bluetoothmodules, sensors, or the like, or any combination thereof. The auxiliarysignals may include status signals (for example, on, off, hibernation,connection, etc.) of the auxiliary function module 220, signalsgenerated through user operations (for example, input and output signalsgenerated by the user through keys, voice input, etc.), signals in theenvironment (for example, audio signals in the environment), or thelike, or any combination thereof. In some embodiments, the auxiliaryfunction module 220 may transmit the received auxiliary signals throughthe flexible circuit board 230 to the other components in the acousticoutput apparatus 200 for processing.

A button module may be configured to control the acoustic outputapparatus 200, so as to implement the interaction between the user andthe acoustic output apparatus 200. The user may send a command to theacoustic output apparatus 200 through the button module to control theoperation of the acoustic output apparatus 200. In some embodiments, thebutton module may include a power button, a playback control button, asound adjustment button, a telephone control button, a recording button,a noise reduction button, a bluetooth button, a return button, or thelike, or any combination thereof. The power button may be configured tocontrol the status (on, off, hibernation, or the like) of the powersource assembly module. The playback control button may be configured tocontrol sound playback by the earphone core 210, for example, playinginformation, pausing information, continuing to play information,playing a previous item, playing a next item, mode selection (e.g. asport mode, a working mode, an entertainment mode, a stereo mode, a folkmode, a rock mode, a bass mode, etc.), playing environment selection(e.g., indoor, outdoor, etc.), or the like, or any combination thereof.The sound adjustment button may be configured to control a soundamplitude of the earphone core 210, for example, increasing the sound,decreasing the sound, or the like. The telephone control button may beconfigured to control telephone answering, rejection, hanging up,dialing back, holding, and/or recording incoming calls. The recordbutton may be configured to record and store the audio information. Thenoise reduction button may be configured to select a degree of noisereduction. For example, the user may select a level or degree of noisereduction manually, or the acoustic output apparatus 200 may select alevel or degree of noise reduction automatically according to a playbackmode selected by the user or detected ambient sound. The bluetoothbutton may be configured to turn on bluetooth, turn off bluetooth, matchbluetooth, connect bluetooth, or the like, or any combination thereof.The return button may be configured to return to a previous menu,interface, or the like.

A sensor may be configured to detect information related to the acousticoutput apparatus 200. For example, the sensor may be configured todetect the user's fingerprint, and transmit the detected fingerprint tothe controller 250. The controller 250 may match the receivedfingerprint with a fingerprint pre-stored in the acoustic outputapparatus 200. If the matching is successful, the controller 250 maygenerate an instruction that may be transmitted to each component toinitiate the sound output apparatus 200. As another example, the sensormay be configured to detect the position of the acoustic outputapparatus 200. When the sensor detects that the acoustic outputapparatus 200 is detached from a user's face, the sensor may transmitthe detected information to the controller 250, and the controller 250may generate an instruction to pause or stop the playback of theacoustic output apparatus 200. In some embodiments, exemplary sensorsmay include a ranging sensor (e.g., an infrared ranging sensor, a laserranging sensor, etc.), a speed sensor, a gyroscope, an accelerometer, apositioning sensor, a displacement sensor, a pressure sensor, a gassensor, a light sensor, a temperature sensor, a humidity sensor, afingerprint sensor, an image sensor, an iris sensor, an image sensor(e.g., a vidicon, a camera, etc.), or the like, or any combinationthereof.

The flexible circuit board 230 may be configured to connect differentcomponents in the acoustic output apparatus 200. The flexible circuitboard 230 may be a flexible printed circuit (FPC). In some embodiments,the flexible circuit board 230 may include one or more bonding padsand/or one or more flexible wires. The one or more bonding pads may beconfigured to connect the one or more components of the acoustic outputapparatus 200 or other bonding pads. One or more leads may be configuredto connect the components of the acoustic output apparatus 200 with onebonding pad, two or more bonding pads, or the like. In some embodiments,the flexible circuit board 230 may include one or more flexible circuitboards. Merely by ways of example, the flexible circuit board 230 mayinclude a first flexible circuit board and a second flexible circuitboard. The first flexible circuit board may be configured to connect twoor more of the microphone, the earphone core 210, and the controller250. The second flexible circuit board may be configured to connect twoor more of the power source assembly 240, the earphone core 210, thecontroller 250, or the like. In some embodiments, the flexible circuitboard 230 may be an integral structure including one or more regions.For example, the flexible circuit board 230 may include a first regionand a second region. The first region may be provided with flexibleleads for connecting the bonding pads on the flexible circuit board 230and other components on the acoustic output apparatus 200. The secondregion may be configured to set one or more bonding pads. In someembodiments, the power source assembly 240 and/or the auxiliary functionmodule 220 may be connected to the flexible circuit board 230 (forexample, the bonding pads) through the flexible leads of the flexiblecircuit board 230.

The power source assembly 240 may be configured to provide electricalpower to the components of the acoustic output apparatus 200. In someembodiments, the power source assembly 240 may include a flexiblecircuit board, a battery, etc. The flexible circuit board may beconfigured to connect the battery and other components of the acousticoutput apparatus 200 (for example, the earphone core 210), and providepower for operations of the other components. In some embodiments, thepower source assembly 240 may also transmit its state information to thecontroller 250 and receive instructions from the controller 250 toperform corresponding operations. The state information of the powersource assembly 240 may include an on/off state, state of charge, timefor use, a charging time, or the like, or any combination thereof. Insome embodiments, the power source assembly may include a body regionand a sealing region. The thickness of the body region may be greaterthan the thickness of the sealing region. A side surface of the sealingregion and a side surface of the body region may have a shape of astair.

According to information of the one or more components of the acousticoutput apparatus 200, the controller 250 may generate an instruction tocontrol the power source assembly 240. For example, the controller 250may generate control instructions to control the power source assembly240 to provide power to the earphone core 210 for generating sound. Asanother example, when the acoustic output apparatus 200 does not receiveinput information within a certain time, the controller 250 may generatea control instruction to control the power source assembly 240 to entera hibernation state. In some embodiments, the power source assembly 240may include a storage battery, a dry battery, a lithium battery, aDaniel battery, a fuel battery, or any combination thereof.

Merely by way of example, the controller 250 may receive a sound signalfrom the user, for example, “play a song”, from the auxiliary functionmodule 220. By processing the sound signal, the controller 250 maygenerate control instructions related to the sound signal. For example,the control instructions may control the earphone core 210 to obtaininformation of songs from the storage module (or other devices). Then anelectric signal for controlling the vibration of the earphone core 210may be generated according to the information.

In some embodiments, the controller 250 may include one or moreelectronic frequency division modules. The electronic frequency divisionmodules may divide a frequency of a source signal. The source signal maycome from one or more sound source apparatus (for example, a memorystoring audio data) integrated in the acoustic output apparatus. Thesource signal may also be an audio signal (for example, an audio signalreceived from the auxiliary function module 220) received by theacoustic output apparatus 200 in a wired or wireless manner. In someembodiments, the electronic frequency division modules may decompose aninput source signal into two or more frequency-divided signalscontaining different frequencies. For example, the electronic frequencydivision module may decompose the source signal into a firstfrequency-divided signal with high-frequency sound and a secondfrequency-divided signal with low-frequency sound. Signals processed bythe electronic frequency division modules may be transmitted to theacoustic driver in the earphone core 210 in a wired or wireless manner.More details of the electronic frequency division modules may bedisclosed elsewhere in the present disclosure, for example, FIG. 8 andthe descriptions thereof.

In some embodiments, the controller 250 may include a central processingunit (CPU), an application-specific integrated circuit (ASIC), anapplication-specific instruction-set processor (ASIP), a graphicsprocessing unit (GPU), a physical processing unit (PPU), a digitalsignal processor (DSP), a field-programmable gate array (FPGA), aprogrammable logic device (PLD), a controller, a microcontroller unit, areduced instruction set computer (RISC), a microprocessor, or the like,or any combination thereof.

In some embodiments, one or more of the earphone core 210, the auxiliaryfunction module 220, the flexible circuit board 230, the power sourceassembly 230, and the controller 250 may be provided in the frame of theglasses 100. Specifically, one or more of the electronic components maybe provided in the hollow structure of the leg 110 and/or the leg 120.The connection and/or communication between the electronic componentsprovided in the leg 110 and/or the leg 120 may be wired or wireless. Thewired connection may include metal cables, fiber optical cables, hybridcables, or the like, or any combination thereof. The wireless connectionmay include a local area network (LAN), a wide area network (WAN), abluetooth, a ZigBee, a near field communication (NFC), or the like, orany combination thereof.

The description of the acoustic output apparatus 200 may be forillustration purposes, and not intended to limit the scope of thepresent disclosure. For those skilled in the art, various changes andmodifications may be made according to the description of the presentdisclosure. For example, the components and/or functions of the acousticoutput apparatus 200 may be changed or modified according to a specificimplementation. For example, the acoustic output apparatus 200 mayinclude a storage component for storing signals containing audioinformation. As another example, the acoustic output apparatus 200 mayinclude one or more processors, which may execute one or more soundsignal processing algorithms for processing sound signals. These changesand modifications may remain within the scope of the present disclosure.

FIG. 3 is a block diagram illustrating an exemplary interactive controlsystem in an acoustic output apparatus according to some embodiments ofthe present disclosure. In some embodiments, at least part of functionsof the interactive control component 300 may be implemented by theauxiliary function module 220 illustrated in FIG. 2. For example,modules and/or units in the interactive control component 300 may beintegrated in the auxiliary function module 220 as part thereof. In someembodiments, the interactive control component 300 may be disposed as anindependent system in the acoustic output apparatus for interactivecontrol (e.g., interactive control in an AR/VR scenario). In someembodiments, the interactive control component 300 may include a buttoncontrol module 310, a voice control module 320, a posture control module330, an auxiliary control module 340, and an indication control module350.

The button control module 310 may be configured to control the acousticoutput apparatus, so as to implement an interaction between a user andthe acoustic output apparatus. The user may send an instruction to theacoustic output apparatus through the button control module 310 tocontrol an operation of the acoustic output apparatus. In someembodiments, the button control module 310 may include a power button, aplayback control button, a sound adjustment button, a telephone controlbutton, a recording button, a noise reduction button, a bluetoothbutton, a return button, or the like, or any combination thereof.Functions of one or more buttons included in the button control module310 may be similar to the button module of the auxiliary function module220 illustrated in FIG. 2, and may not be repeated here. In someembodiments, the one or more buttons included in the button controlmodule 310 may be disposed on the glasses 100. For example, the powerbutton may be disposed on the leg 110, the leg 120, or the lens ring130. In some embodiments, the one or more buttons included in the buttoncontrol module 310 may be disposed in one or more control devices. Theglasses 100 may be connected to the one or more control devices via awired or wireless connection. The control devices may transmitinstructions input by the user to the glasses 100, so as to controloperations of the one or more components in the glasses 100.

In some embodiments, the button control module 310 may include two formsincluding physical buttons and virtual buttons. For example, when thebutton control module 310 includes physical buttons, the physicalbuttons may be disposed outside a housing of an acoustic outputapparatus (e.g., the glasses 100). When the user wears the acousticoutput apparatus, the physical buttons may not contact with human skinand may be exposed on the outside to facilitate user operations on thephysical button. In some embodiments, an end surface of each button inthe button control module 310 may be provided with an identifiercorresponding to its function. In some embodiments, the identifier mayinclude text (e.g., Chinese and/or English), symbols (e.g., the volumeplus button may be marked with “+”, and the volume minus button may bemarked with “−”), or the like, or any combination thereof. In someembodiments, the identifier may be set on the button by means of laserprinting, screen printing, pad printing, laser filler, thermalsublimation, hollow text, or the like, or any combination thereof. Insome embodiments, the identifier on the button may also be disposed onthe surface of the housing around the buttons. In some embodiments,control programs installed in the acoustic output apparatus may generatevirtual buttons on a touch screen having an interaction function. Theuser may select the function, volume, file, etc. of the acoustic outputapparatus through the virtual button. In addition, the acoustic outputapparatus may have a combination of a touch screen and a physicalbutton. In some embodiments, the touch screen may be or include avirtual user-interface (UI). Taking an acoustic output apparatuscustomized for AR as an example, the user may interact with the acousticoutput apparatus via the virtual UI. One or more virtual buttons may beprovided on the virtual UI. The user may select and/or touch the one ormore virtual buttons to control the acoustic output apparatus. Forexample, the user may select a virtual sound adjustment button on thevirtual UI to adjust a volume of an audio played in the virtual UI.Alternatively or additionally, the user may also adjust the volume ofthe audio played in the virtual UI by selecting one or more physicalbuttons disposed on the acoustic output apparatus.

In some embodiments, the button control module 310 may implementdifferent interaction functions based on different operations of theuser. For example, the user may click a button (a physical button or avirtual button) once to pause or start a music, a recording, etc. Asanother example, the user may tap the button twice quickly to answer acall. As a further example, the user may click the button regularly(e.g., clicking once every second for a total of two clicks) to start arecording. In some embodiments, the operations of the user may includeclicking, swiping, scrolling, or the like, or any combination thereof.For example, the user may slide up and down on a surface of a buttonusing his/her finger to increase or decrease volume.

In some embodiments, the functions corresponding to the button controlmodule 310 may be customized by the user. For example, the user mayadjust the functions that the button control module 310 can implementthrough applications settings. In addition, operation modes (e.g., thenumber of clicks and swipe gestures) to achieve a specific function mayalso be set by the user through the application. For example, anoperation instruction for answering a call may be set from one click totwo clicks, and an operation instruction for switching to the next orthe previous song may be set from two clicks to three clicks. Accordingto the above user-defined methods, the operation modes of the buttoncontrol module 310 may conform operating habits of the user, which mayavoid operating errors and improve user experience.

In some embodiments, the acoustic output apparatus may be connected toan external device through the button control module 310. For example,the acoustic output apparatus may be connected to a mobile phone througha button configured to control a wireless connection (e.g., a buttoncontrolling a Bluetooth module). Optionally, after a connection isestablished, the user may directly operate the acoustic output apparatuson the external device (e.g., the mobile phone) to implement one or morefunctions.

The voice control module 320 may be configured to control the acousticoutput apparatus based on voices received from the user. FIG. 4 is ablock diagram illustrating an exemplary voice control module in anacoustic output apparatus according to some embodiments of the presentdisclosure. In some embodiments, as illustrated in FIG. 4, the voicecontrol module 320 may include a receiving unit 322, a processing unit324, a recognition unit 326, and a control unit 328.

The receiving unit 322 may be configured to receive a voice controlinstruction from a user (and/or a smart device) and send the voicecontrol instruction to the processing unit 324. In some embodiments, thereceiving unit 322 may include one or more microphones, or a microphonearray. The one or more microphones or the microphone array may be housedwithin the acoustic output apparatus or in another device connected tothe acoustic output apparatus. In some embodiments, the one or moremicrophones or the microphone array may be generic microphones. In someembodiments, the one or more microphones or the microphone array may becustomized for VR and/or AR. In some embodiments, the receiving unit 322may be positioned so as to receive audio signals (e.g., speech/voiceinput by the user to enable a voice control functionality) proximate tothe acoustic output apparatus. For example, the receiving unit 322 mayreceive a voice control instruction of the user wearing the acousticoutput apparatus and/or other users proximate to or interacting with theuser. In some embodiments, when the receiving unit 322 receives a voicecontrol instruction issued by a user, for example, when the receivingunit 322 receives a voice control instruction of “start playing”, thevoice control instruction may be sent to the processing unit 324.

The processing unit 324 may be communicatively connected with thereceiving unit 322. In some embodiments, when the processing unit 324receives a voice control instruction of the user from the receiving unit322, the processing unit 324 may generate an instruction signal based onthe voice control instruction, and further send the instruction signalto the recognition unit 326.

The recognition unit 326 may be communicatively connected with theprocessing unit 324 and the control unit 328, and configured to identifywhether the instruction signal matches a preset signal. The presetsignal may be previously input by the user and saved in the acousticoutput apparatus (e.g., in a storage module). For example, therecognition unit 326 may perform a speech recognition process and/or asemantic recognition process on the instruction signal and determinewhether the instruction signal matches the preset signal. In response toa determination that the instruction signal matches the preset signal,the recognition unit 326 may send a matching result to the control unit328.

The control unit 328 may control the operation of the acoustic outputapparatus based on the instruction signal and the matching result.Taking an acoustic output apparatus customized for VR as an example, theacoustic output apparatus may be positioned to determine a location ofthe user wearing the acoustic output apparatus. When the user isproximate to or facing towards a historical site, an audio associatedwith the historical site may be recommended to the user via a virtualinterface. The user may send a voice control instruction of “startplaying” for paly the audio. The receiving unit 322 may receive thevoice control instruction and send it to the the processing unit 324.The processing unit 324 may generate an instruction signal according tothe voice control instruction and send the instruction signal to therecognition unit 326. When the the recognition unit 326 determines thatthe instruction signal corresponding to the voice control instructionmatches a preset signal, the control unit 328 may execute the voicecontrol instruction automatically. That is, the control unit 328 maycause the acoustic output apparatus to start playing the audioimmediately on the virtual interface.

In some embodiments, the voice control module 320 may further include astorage module, which may be communicatively connected with thereceiving unit 322, the processing unit 324, and the recognition unit326. The receiving unit 322 may receive a preset voice controlinstruction and send it to the processing unit 324. The processing unit324 may generate a preset signal according to a preset voice controlinstruction and sends the preset signal to the storage module. When therecognition unit 326 needs to match the instruction signal received bythe receiving unit 322 with the preset signal, the storage module maysend the preset signal to the recognition unit 326 via the communicationconnection.

In some embodiments, the processing unit 324 in the voice control module320 may further perform a denoise process on the voice controlinstruction. The denoising process may refer to removing ambient soundincluded in the voice control instruction. In some embodiments, forexample, in a complex environment, the receiving unit 322 may receive avoice control instruction and send it to the processing unit 324, beforethe processing unit 324 generates a corresponding instruction signalaccording to the voice control instruction, in order to avoid ambientsounds from disturbing the recognition process of the recognition unit326, the voice control instruction may be denoised. For example, whenthe receiving unit 322 receives a voice control instruction issued by auser on an outdoor road, the voice control instruction may include noisyenvironmental sounds such as vehicle driving, whistle on the road. Theprocessing module 302 may reduce the influence of the environmentalsound on the voice control instruction through the denoise process.

The posture control module 330 may be configured to control the acousticoutput apparatus based on a posture instruction of the user. Forexample, the posture control module 330 may recognize an action and/or aposture of the user and perform a function corresponding to the actionand/or the posture. In some embodiments, posture control module 330 mayinclude one or more sensors for recognizing the an action and/or aposture of the user. Exemplary sensors may include include anoptical-based tracking sensor (e.g., an optical camera), anaccelerometer, a magnetometer, a gyroscope, a radar, a distance sensor,a speed sensor, a positioning sensor, a displacement sensor, a pressuresensor, a gas sensor, a light sensor, a temperature sensor, a humiditysensor, a fingerprint sensor, an image sensor, an iris sensor, or thelike, or any combination thereof. In some embodiments, the one or moresensors may detect a change in the user's orientation, such as a turningof the torso or an about-face movement. In some embodiments, the one ormore sensors may sense gestures of the user or a body part (e.g., head,torso, limbs) of the user. In some embodiments, the one or more sensorsmay generate sensor data regarding the orientation and/or the gesturesof the user accordingly and transmit the sensor data to, for example, aprocessing unit included in the posture control module 330. The posturecontrol module 330 may analyze the sensor data and identify an actionand/or a posture. Further, the posture control module 330 may controlthe the acoustic output apparatus to perform a function corresponding tothe identified action and/or posture.

In some embodiments, the identified action and/or posture may include acount and/or frequency of blinking of the user, a count, direction,and/or frequency of nodding and/or shaking head of the user, and acount, direction, frequency, and form of hand movements of the user,etc. For example, the user may interact with the acoustic outputapparatus by blinking a certain times and/or at a certain frequency.Specifically, the user may turn on the sound playback function of theacoustic output device by blinking twice, and turn off the Bluetoothfunction of the acoustic output device by blinking three times. Asanother example, the user may interact with the acoustic outputapparatus by nodding a certain count, in a certain direction and/or at acertain frequency. Specifically, the user may answer a call by noddingonce, and reject the call or turn off music playback by shaking his/herhead once. As a further example, the user may interact with the acousticoutput apparatus through a gesture, or the like. Specifically, the usermay open the acoustic output apparatus by extending his/her palm, closethe acoustic output apparatus by holding his/her fist, take a picture bymaking a “scissor” gesture, or the like. As still a further example, inan AR scenario, the user may interact with the acoustic output apparatusvia a virtual UI. Specifically, the acoustic output apparatus mayprovide a plurality of choices corresponding to spatially delineatedzones in an array defined relative to a physical position of theacoustic output apparatus. The user may shake his/her head to switchbetween different zones, or blink once to expand a zone.

The auxiliary control module 340 may be configured to detect workingstates of the acoustic output apparatus and components thereof, andcontrol the acoustic output apparatus and the components thereofaccording to the working states (e.g., a placement state, a worn state,whether it has been tapped, an angle of inclination, power, etc.). Forexample, when detecting that the acoustic output apparatus is not worn,the auxiliary control module 340 may power off one or more components ofthe acoustic output apparatus after a preset time (e.g., 15 s). Asanother example, when detecting regular taps (e.g., two consecutiverapid taps) on the acoustic output apparatus, the auxiliary controlmodule 340 may pause the output of the acoustic output apparatus. As afurther example, when detecting a state of low power of a power moduleincluded in the acoustic output apparatus, the auxiliary control module340 may control the acoustic output apparatus to output a prompt soundfor charging.

In some embodiments, the auxiliary control module 340 may include adetector, a sensor, a gyroscope, or the like. The detector may include abattery detector, a weight detector, an infrared detector, a mechanicaldetector, or the like, or any combination thereof. The sensor mayinclude a temperature sensor, a humidity sensor, a pressure sensor, adisplacement sensor, a flow sensor, a liquid level sensor, a forcesensor, a speed sensor, a torque sensor, or the like, or any combinationthereof. The gyroscope may be configured to detect a placement directionof the acoustic output apparatus. For example, when the gyroscopedetects that a bottom of the acoustic output apparatus is placed upward,the auxiliary control module 340 may turn off the power module after apreset time (e.g., 20 s). The gyroscope may also communicate with agyroscope of an external device (e.g., a mobile phone) directly orthrough a communication module, such that the auxiliary control module340 may control the acoustic output apparatus based on detection resultsof the gyroscope included in the auxiliary control module 340 and thegyroscope of the external device. For example, when the gyroscopeincluded in the auxiliary control module 340 detects that a bottom ofthe acoustic output apparatus is placed upward, and the gyroscope of theexternal device detects that the external device is in a static state,the auxiliary control module 340 may turn off the power module after apreset time (e.g., 15 s).

The indication control module 350 may be configured to indicate workingstates of the acoustic output apparatus. In some embodiments, theindication control module 350 may include an indicator. The indicatormay emit one or more colored lights and/or blink different times toindicate different states (eg, on, off, volume, power, tone, speed ofspeech, etc.) of the acoustic output apparatus. For example, when theacoustic output apparatus is turned on, the indicator may emit greenlight, and when the acoustic output apparatus is turned off, theindicator may emit red light. As another example, when the acousticoutput apparatus is turned on, the indicator may blink three times, andwhen the acoustic output apparatus is turned off, the indicator mayblink one time. As a further example, when the acoustic output apparatusprovides an ARNR scenario, the indicator may emit green light, and whenthe acoustic output apparatus stops providing an ARNR scenario, theindicator may emit red light. In some embodiments, the indicator mayalso emit light of one or more colors and/or blink different times toindicate a connection state of a communication module in the acousticoutput apparatus. For example, when the communication module connectswith an external device, the indicator may emit green light, and whenthe communication module fails to connect with the external device, theindicator may emit red light. As a further example, when thecommunication module fails to connect with the external device, theindicator may keep flashing. In some embodiments, the indicator may alsoemit light of one or more colors and/or blink different times toindicate the power of a power module. For example, when the power moduleis out of power, the indicator may emit red light. As another example,when the power module is out of power, the indicator may keep flashing.In some embodiments, the indicator may be disposed at any position ofthe acoustic output apparatus. For example, the indicator may bedisposed on the leg 110, the leg 120, or the lens ring 130 of theglasses 100.

The modules in the interactive control component 300 may be connected toor communicate with each other via a wired connection or a wirelessconnection. The wired connection may include a metal cable, an opticalcable, a hybrid cable, or the like, or any combination thereof. Thewireless connection may include a Local Area Network (LAN), a Wide AreaNetwork (WAN), a Bluetooth, a ZigBee, a Near Field Communication (NFC),or the like, or any combination thereof. Two or more of the modules maybe combined as a single module, and any one of the modules may bedivided into two or more units. In some embodiments, the interactivecontrol component 300 may include one or more other modules and/orunits, and one or more modules and/or units included in the interactivecontrol component 300 may be unnecessary. For example, the indicationcontrol module 350 may also include a voice indication unit which may beconfigured to indicate working states of the acoustic output apparatusby using pre-stored voices. As another example, the auxiliary controlmodule 340 may be unnecessary. At least part of functions of theauxiliary control module 340 may be implemented by other modulesincluded in the interactive control component 300.

FIG. 5 is a schematic diagram illustrating an exemplary two pointsources according to some embodiments of the present disclosure. Inorder to further explain the effect of the setting of the sound guidingholes on the acoustic output apparatus, and considering that the soundmay be regarded as propagating outwards from the sound guiding holes,the present disclosure may describe sound guiding holes on an acousticoutput apparatus as sound sources for externally outputting sound.

Just for the convenience of description and for the purpose ofillustration, when sizes of the sound guiding holes on the acousticoutput apparatus are small, each sound guiding hole may be approximatelyregarded as a point source (or referred to as a point sound source or asound source). In some embodiments, any sound guiding hole provided onthe acoustic output apparatus for outputting sound may be approximatedas a single point (sound) source on the acoustic output apparatus. Thesound field pressure p generated by a single point source may satisfyEquation (1):

$\begin{matrix}{{p = {\frac{j\omega \rho_{0}}{4\pi r}Q_{0}{{\exp j}\left( {{\omega t} - {kr}} \right)}}},} & (1)\end{matrix}$

where ω denotes an angular frequency, ρ₀ denotes an air density, rdenotes a distance between a target point and the point source, Q₀denotes a volume velocity of the point source, and k denotes the wavenumber. It may be concluded that the magnitude of the sound fieldpressure of the point source at the target point is inverselyproportional to the distance from the target point to the point source.

It should be noted that the sound guiding holes for outputting sound aspoint sources may only serve as an explanation of the principle andeffect of the present disclosure, and may not limit the shapes and sizesof the sound guiding holes in practical applications. In someembodiments, if an area of a sound guiding hole is large enough, thesound guiding hole may also be equivalent to a planar acoustic source.In some embodiments, the point source may also be realized by otherstructures, such as a vibration surface and a sound radiation surface.For those skilled in the art, without creative activities, it may beknown that sounds produced by structures such as a sound guiding hole, avibration surface, and an acoustic radiation surface may be similar to apoint source at the spatial scale discussed in the present disclosure,and may have similar sound propagation characteristics and the similarmathematical description method. Further, for those skilled in the art,without creative activities, it may be known that the acoustic effectachieved by “an acoustic driver may output sound from at least two firstsound guiding holes” described in the present disclosure may alsoachieve the same effect by other acoustic structures, for example, “atleast two acoustic drivers each may output sound from at least oneacoustic radiation surface.” According to actual situations, otheracoustic structures may be selected for adjustment and combination, andthe same acoustic output effect may also be achieved. The principle ofradiating sound outward with structures such as surface sound sourcesmay be similar to that of point sources, and may not be repeated here.

As mentioned above, at least two sound guiding holes corresponding to asame acoustic driver may be set on the acoustic output apparatusprovided in the specification. In this case, two point sources may beformed, which may reduce sound transmitted to the surroundingenvironment. For convenience, sound output from the acoustic outputapparatus to the surrounding environment may be referred to as afar-field leakage since it can be heard by others in the environment.The sound output from the acoustic output apparatus to the ears of theuser wearing the acoustic output apparatus may be referred to as anear-field sound since a distance between the acoustic output apparatusand the user is relatively short. In some embodiments, the sound outputfrom two sound guiding holes (i.e., two point sources) may have acertain phase difference. When the distance between the two pointsources and the phase difference of the two point sources meet a certaincondition, the acoustic output apparatus may output different soundeffects in the near field (for example, the position of the user's ear)and the far field. For example, if the phases of the point sourcescorresponding to the two sound guiding holes are opposite, that is, anabsolute value of the phase difference between the two point sources is180 degrees, the far-field leakage may be reduced according to theprinciple of reversed phase cancellation. More details regarding anenhancement of the acoustic output apparatus by adjusting the amplitudeand/or phase of each point source may be found in Internationalapplication No. PCT/CN2019/130884, filed on Dec. 31, 2019, the entirecontent of which may be hereby incorporated by reference.

As shown in FIG. 5, a sound field pressure p generated by two pointsources may satisfy Equation (2):

$\begin{matrix}{{p = {{\frac{A_{1}}{r_{1}}{{\exp j}\left( {{\omega t} - {kr}_{1} + \phi_{1}} \right)}} + {\frac{A_{2}}{r_{2}}{{\exp j}\left( {{\omega t} - {kr}_{2} + \phi_{2}} \right)}}}},} & (2)\end{matrix}$

where A₁ and A₂ denote intensities of the two point sources, and φ₁ andφ₂ denote phases of the two point sources, respectively, d denotes adistance between the two point sources, and r₁ and r₂ may satisfyEquation (3):

$\begin{matrix}\left\{ {\begin{matrix}{r_{1} = \sqrt{r^{2} + \left( \frac{d}{2} \right)^{2} - {2*r*\frac{d}{2}*{cos\theta}}}} \\{r_{2} = \sqrt{r^{2} + \left( \frac{d}{2} \right)^{2} + {2*r*\frac{d}{2}*{cos\theta}}}}\end{matrix},} \right. & \left. 3 \right)\end{matrix}$

where r denotes a distance between a target point and the center of thetwo point sources in the space, and θ indicates an angle between a lineconnecting the target point and the center of the two point sources andthe line on which the two point source is located.

It may be concluded from Equation (3) that a magnitude of the soundpressure pat the target point in the sound field may relate to theintensity of each point source, the distance d, the phase of each pointsource, and the distance r.

Two point sources with different output effects may be achieved bydifferent settings of sound guiding holes, such that the volume of thenear-field sound may be improved, and the far-field leakage may bereduced. For example, an acoustic driver may include a vibrationdiaphragm. When the vibration diaphragm vibrates, sounds may betransmitted from the front and rear sides of the vibration diaphragm,respectively. The front side of the vibration diaphragm in the acousticoutput apparatus may be provided with a front chamber for transmittingsound. The front chamber may be coupled with a sound guiding holeacoustically. The sound on the front side of the vibration diaphragm maybe transmitted to the sound guiding hole through the front chamber andfurther transmitted outwards. The rear side of the vibration diaphragmin the acoustic output apparatus may be provided with a rear chamber fortransmitting sound. The rear chamber may be coupled with another soundguiding hole acoustically. The sound on the rear side of the vibrationdiaphragm may be transmitted to the sound guiding hole through the rearchamber and propagate further outwards. It should be noted that, whenthe vibration diaphragm is vibrating, the front side and the rear sideof the vibration diaphragm may generate sounds with opposite phases. Insome embodiments, the structures of the front chamber and rear chambermay be specially set so that the sound output by the acoustic driver atdifferent sound guiding holes may meet a specific condition. Forexample, lengths of the front chamber and rear chamber may be speciallydesigned such that sounds with a specific phase relationship (e.g.,opposite phases) may be output at the two sound guiding holes. As aresult, a problem that the acoustic output apparatus has a low volume inthe near-field and a sound leakage in the far-field may be effectivelyresolved.

Under certain conditions, compared to the volume of a far-field leakageof a single point source, the volume of a far-field leakage of two pointsources may increase with the frequency. In other words, the leakagereduction capability of the two point sources in the far field maydecrease with the frequency increases. For further description, a curveillustrating a relationship between a far-field leakage and a frequencymay be described in connection with FIG. 6.

FIG. 6 is a schematic diagram illustrating a variation of a soundleakage of two point sources and a single point source as a function offrequency according to some embodiments of the present disclosure. Thedistance between the two point sources in FIG. 6 may be fixed, and thetwo point sources may have a substantially same amplitude and oppositephases. The dotted line may indicate a variation curve of a volume of aleaked sound of the single point source at different frequencies. Thesolid line may indicate a variation curve of a volume of a leaked soundof the two point sources at different frequencies. The abscissa of thediagram may represent the sound frequency (f), and the unit may be Hertz(Hz). The ordinate of the diagram may use a normalization parameter a toevaluate the volume of a leaked sound. The parameter a may be determinedaccording to Equation (4):

$\begin{matrix}{{\alpha = \frac{\left| P_{far} \right|^{2}}{\left| P_{ear} \right|^{2}}},} & (4)\end{matrix}$

where P_(far) represents the sound pressure of the acoustic outputapparatus in the far-field (i.e., the sound pressure of the far-fieldsound leakage). P_(ear) represents the sound pressure around the user'sears (i.e., the sound pressure of the near-field sound). The larger thevalue of a, the larger the far-field leakage relative to the near-fieldsound heard will be, indicating that a poorer capability of the acousticoutput apparatus for reducing the far-field leakage.

As shown in FIG. 6, when the frequency is below 6000 Hz, the far-fieldleakage produced by the two point sources may be less than the far-fieldleakage produced by the single point source, and may increase as thefrequency increases. When the frequency is close to 10000 Hz (forexample, about 8000 Hz or above), the far-field leakage produced by thetwo point sources may be greater than the far-field leakage produced bythe single point source. In some embodiments, a frequency correspondingto an intersection of the variation curves of the two point sources andthe single point source may be determined as an upper limit frequencythat the two point sources are capable of reducing a sound leakage.

For illustrative purposes, when the frequency is relatively small (forexample, in a range of 100 Hz˜1000 Hz), the capability of reducing asound leakage of the two point sources may be strong (e.g., the value ofa is small, such as below −80 dB). In such a frequency band, an increaseof the volume of the sound heard by the user may be determined as anoptimization goal. When the frequency is larger (for example, in a rangeof 1000 Hz˜8000 Hz), the capability of reducing a sound leakage of thetwo point sources may be weak (e.g., above −80 dB). In such a frequencyband, a decrease of the sound leakage may be determined as theoptimization goal.

According to FIG. 6, it may be possible to determine a frequencydivision point based on the variation tendency of the two point sources'capability of reducing a sound leakage. Parameters of the two pointsources may be adjusted according to the frequency division point so asto reducing the sound leakage of the acoustic output apparatus. Forexample, the frequency corresponding to a of a specific value (forexample, −60 dB, −70 dB, −80 dB, −90 dB, etc.) may be used as thefrequency division point. Parameters of the two point sources may bedetermined to improve the near-field sound in a frequency band below thefrequency division point, and/or to reduce the far-field sound leakagein a frequency band above the frequency division point. In someembodiments, a high-frequency band with a high frequency (for example, asound output from a high-frequency acoustic driver) and a low-frequencyband with a low frequency (for example, a sound output from alow-frequency acoustic driver) may be determined based on the frequencydivision point. More details of the frequency division point may bedisclosed elsewhere in the present disclosure, for example, FIG. 8 andthe descriptions thereof.

In some embodiments, the method for measuring and determining the soundleakage may be adjusted according to the actual conditions. For example,a plurality of points on a spherical surface centered by s center pointof the two point sources with a radius of r (for example, 40 centimeter)may be identified, and an average value of amplitudes of the soundpressure at the plurality of points may be determined as the value ofthe sound leakage. The distance between the near-field listeningposition and the point sources may be far less than the distance betweenthe point sources and the spherical surface for measuring the far-fieldleakage. Optionally, the ratio of the distance from the near-fieldlistening position to the center of the two point sources to the radiusr may be less than 0.3, 0.2, 0.15, or 0.1. As another example, one ormore points of the far-field may be taken as the position for measuringthe sound leakage, and the sound volume of the position may be taken asthe value of the sound leakage. As another example, a center of the twopoint sources may be used as a center of a circle at the far field, andsound pressure amplitudes of two or more points evenly distributed atthe circle according to a certain spatial angle may be averaged as thevalue of the sound leakage. These methods may be adjusted by thoseskilled in the art according to actual conditions, and is not intendedto be limiting.

According to FIG. 6, it may be concluded that in the high-frequency band(a higher frequency band determined according to the frequency divisionpoint), the two point sources may have a weak capability to reduce asound leakage. In the low-frequency band (a lower frequency banddetermined according to the frequency division point), the two pointsources may have a strong capability to reduce a sound leakage. At acertain sound frequency, if the distance between the two point sourceschanges, its capability to reduce a sound leakage may be changed, andthe difference between volume of the sound heard by the user (alsoreferred to as “heard sound”) and volume of the leaked sound may also bechanged. For a better description, the curve of a far-field leakage as afunction of the distance between the two point sources may be describedwith reference to FIGS. 7A and 7B.

FIGS. 7A and 7B are exemplary graphs illustrating a volume of anear-field sound and a volume of a far-field leakage as a function of adistance between two point sources according to some embodiments of thepresent disclosure. FIG. 7B may be generated by performing anormalization on the graph in FIG. 7A.

In FIG. 7A, a solid line may represent a variation curve of the volumeof the two point sources as a function of the distance between the twopoint sources, and the dotted line may represent the variation curve ofthe volume of the leaked sound of the two point sources as a function ofthe distance between the two point sources. The abscissa may represent adistance ratio d/d0 of the distance d of the two point sources to areference distance d0. The ordinate may represent a sound volume (theunit is decibel dB). The distance ratio d/d0 may reflect a variation ofthe distance between the two point sources. In some embodiments, thereference distance d0 may be selected within a specific range. Forexample, d0 may be a specific value in the range of 2.5 mm˜10 mm, e.g.,d0 may be 5 mm. In some embodiments, the reference distance d0 may bedetermined based on a listening position. For example, the distancebetween the listening position to the nearest point source may be takenas the reference distance d0. It should be known that the referencedistance d0 may be flexibly selected from any other suitable valuesaccording to the actual conditions, which is not limited here. Merely byway of example, in FIG. 7A, d0 may be 5 mm.

When the sound frequency is a constant, the volume of the sound heard bythe user and volume of the leaked sound of the two point sources mayincrease as the distance between the two point sources increases. Whenthe distance ratio d/d0 of is less than a threshold ratio, an increase(or increment) in the volume of the sound heard by the user may belarger than an increase (or increment) in the volume of the leaked soundas the distance between two point sources increases. That is to say, theincrease in volume of the sound heard by the user may be moresignificant than the increase in volume of the leaked sound. Forexample, as shown in FIG. 7A, when the distance ratio d/d0 is 2, thedifference between the volume of the sound heard by the user and thevolume of the leaked sound may be about 20 dB. When the distance ratiod/d0 is 4, the difference between the volume of the sound heard by theuser and the volume of the leaked sound may be about 25 dB. In someembodiments, when the distance ratio d/d0 reaches the threshold ratio,the ratio of the volume of the sound heard by the user to the volume ofthe leaked sound of the two point sources may reach a maximum value. Atthis time, as the distance of the two point sources further increases,the curve of the volume of the sound heard by the user and the curve ofthe volume of the leaked sound may gradually go parallel, that is, theincrease in volume of the sound heard by the user and the increase involume of the leaked sound may remain substantially the same. Forexample, as shown in FIG. 7B, when the distance ratio d/d0 is 5, 6, or7, the difference between the volume of the sound heard by the user andthe volume of the leaked sound may remain substantially the same, bothof which may be about 25 dB. That is, the increase in volume of thesound heard by the user may be the same as the increase in volume of theleaked sound. In some embodiments, the threshold ratio of the distanceratio d/d0 of the two point sources may be in the range of 0˜7. Forexample, the threshold ratio of d/d0 may be set in the range of 0.5˜4.5.As another example, the threshold ratio of d/d0 may be set in the rangeof 1˜4.

In some embodiments, the threshold ratio value may be determined basedon the variation of the difference between the volume of the sound heardby the user and the volume of the leaked sound of the two point sourcesof FIG. 7A. For example, the ratio corresponding to the maximumdifference between the volume of the sound heard by the user and thevolume of the leaked sound may be determined as the threshold ratio. Asshown in FIG. 7B, when the distance ratio d/d0 is less than thethreshold ratio (e.g., 4), a curve of a normalized sound heard by theuser (also referred to as “normalized heard sound”) may show an upwardtrend (the slope of the curve is larger than 0) as the distance betweenthe two point sources increases. That is, the increase in sound heard bythe user volume may be greater than the increase in volume of the leakedsound. When the distance ratio d/d0 is greater than the threshold ratio,the slope of the curve of the normalized sound heard by the user maygradually approach 0 as the distance between the two point sourcesincreases. That is to say, the increase in volume of the sound heard bythe user may be no longer greater than the increase in volume of theleaked sound as the distance between the two point sources increases.

According to the descriptions above, if the listening position is fixed,the parameters of the two point sources may be adjusted by certainmeans. It may be possible to achieve an effect that the volume of thenear-field sound has a significant increase while the volume of thefar-field leakage only increases slightly (i.e., the increase in thevolume of the near-field sound is greater than the volume of thefar-field leakage). For example, two or more sets of two point sources(such as a set of high-frequency two point sources and a set oflow-frequency two point sources) may be used. For each set, the distancebetween the point sources in the set are adjusted by a certain means, sothat the distance between the high-frequency two point sources may beless than the distance between the low-frequency two point sources. Thelow-frequency two point sources may have a small sound leakage (thecapability to reduce the sound leakage is strong), and thehigh-frequency two point sources have a large sound leakage (thecapability to reduce the sound leakage is weak). The volume of the soundheard by the user may be significantly larger than the volume of theleaked sound if a smaller distance between the two point sources is setin the high-frequency band, thereby reducing the sound leakage.

In some embodiments, each acoustic driver may have a corresponding pairof sound guiding holes. The distance between the sound guiding holescorresponding to each acoustic driver may affect the volume of thenear-field sound transmitted to the user's ears and the volume of thefar-field leakage transmitted to the environment. In some embodiments,if the distance between the sound guiding holes corresponding to ahigh-frequency acoustic driver is less than that between the soundguiding holes corresponding to a low-frequency acoustic driver, thevolume of the sound heard by the user may be increased and the soundleakage may be reduced, thereby preventing the sound from being heard byothers near the user of the acoustic output apparatus. According to theabove descriptions, the acoustic output apparatus may be effectivelyused as an open earphone even in a relatively quiet environment.

FIG. 8 is a schematic diagram illustrating an exemplary acoustic outputapparatus according to some embodiments of the present disclosure. Asshown in FIG. 8, the acoustic output apparatus 800 may include anelectronic frequency division module 810, an acoustic driver 840, anacoustic driver 850, an acoustic route 845, an acoustic route 855, atleast two first sound guiding holes 847, and at least two second soundguiding holes 857. In some embodiments, the acoustic output apparatus800 may further include a controller (not shown in the figure). Theelectronic frequency division module 810 may be part of the controllerand configured to generate electrical signals that are input intodifferent acoustic drivers. The connection between different componentsin the acoustic output apparatus 800 may be wired and/or wireless. Forexample, the electronic frequency division module 810 may send signalsto the acoustic driver 840 and/or the acoustic driver 850 through awired transmission or a wireless transmission.

The electronic frequency division module 810 may divide the frequency ofa source signal. The source signal may come from one or more soundsource apparatus (for example, a memory storing audio data). The soundsource apparatus may be part of the acoustic output apparatus 800 or anindependent device. The source signal may be an audio signal that isreceived by the acoustic output apparatus 800 via a wired or wirelessmeans. In some embodiments, the electronic frequency division module 810may decompose the source signal into two or more frequency-dividedsignals having different frequencies. For example, the electronicfrequency division module 110 may decompose the source signal into afirst frequency-divided signal (or frequency-divided signal 1) having ahigh-frequency sound and a second frequency-divided signal (orfrequency-divided signal 2) having a low-frequency sound. Forconvenience, a frequency-divided signal having the high-frequency soundmay be referred to as a high-frequency signal, and a frequency-dividedsignal having the low-frequency sound may be referred to as alow-frequency signal.

For the purposes of description, a low-frequency signal described in thepresent disclosure may refer to a sound signal with a frequency in afirst frequency range (or referred to as a low frequency range). Ahigh-frequency signal may refer to a sound signal with a frequency in asecond frequency range (or referred to as a high frequency range). Thefirst frequency range and the second frequency range may or may notinclude overlapping frequency ranges. The second frequency range mayinclude frequencies higher than the first frequency range. Merely by wayof example, the first frequency range may include frequencies below afirst threshold frequency. The second frequency range may includefrequencies above a second threshold frequency. The first thresholdfrequency may be lower than the second threshold frequency, or equal tothe second threshold frequency, or higher than the second thresholdfrequency. For example, the first threshold frequency may be lower thanthe second threshold frequency (for example, the first thresholdfrequency may be 600 Hz and the second threshold frequency may be 700Hz), which means that there is no overlap between the first frequencyrange and the second frequency range. As another example, the firstthreshold frequency may be equal to the second frequency (for example,both the first threshold frequency and the second threshold frequencymay be 650 Hz or any other frequency values). As another example, thefirst threshold frequency may be higher than the second thresholdfrequency, which indicates that there is an overlap between the firstfrequency range and the second frequency range. In such cases, in someembodiments, the difference between the first threshold frequency andthe second threshold frequency may not exceed a third thresholdfrequency. The third threshold frequency may be a fixed value, forexample, 20 Hz, 50 Hz, 100 Hz, 150 Hz, or 200 Hz. Optionally, the thirdthreshold frequency may be a value related to the first thresholdfrequency and/or the second threshold frequency (for example, 5%, 10%,15%, etc., of the first threshold frequency). Alternatively, the thirdthreshold frequency may be a value flexibly set by the user according tothe actual needs, which may be not limited herein. It should be notedthat the first threshold frequency and the second threshold frequencymay be flexibly set according to different situations, and are notlimited herein.

In some embodiments, the electronic frequency division module 810 mayinclude a frequency divider 815, a signal processor 820, and a signalprocessor 830. The frequency divider 815 may be used to decompose thesource signal into two or more frequency-divided signals containingdifferent frequency components, for example, a frequency-divided signal1 having a high-frequency sound component and a frequency-divided signal2 having a low-frequency sound component. In some embodiments, thefrequency divider 815 may be any electronic device that may implementthe signal decomposition function, including but not limited to one of apassive filter, an active filter, an analog filter, a digital filter, orany combination thereof. In some embodiments, the frequency divider 815may divide the source signal based on one or more frequency divisionpoints. A frequency division point may refer to a specific frequencydistinguishing the first frequency range and the second frequency range.For example, when there is an overlapping frequency range between thefirst frequency range and the second frequency range, the frequencydivision point may be a feature point within the overlapping frequencyrange (for example, a low-frequency boundary point, a high-frequencyboundary point, a center frequency point, etc., of the overlappingfrequency range). In some embodiments, the frequency division point maybe determined according to a relationship between the frequency and thesound leakage of the acoustic output apparatus (for example, the curvesshown in FIGS. 6, 7A, and 7B). For example, considering that the soundleakage of the acoustic output apparatus changes with the frequency, afrequency point corresponding to the volume of the leaked soundsatisfying a certain condition may be selected as the frequency divisionpoint, for example, 1000 Hz shown in FIG. 6. In some alternativeembodiments, the user may specify a specific frequency as the frequencydivision point directly. For example, considering that the frequencyrange of sounds that the human ear may hear is 20 Hz-20 kHz, the usermay select a frequency point in this range as the frequency divisionpoint. For example, the frequency division point may be 600 Hz, 800 Hz,1000 Hz, 1200 Hz, or the like. In some embodiments, the frequencydivision point may be determined based on the performance of theacoustic drivers 840 and 850. For example, considering that alow-frequency acoustic driver and a high-frequency acoustic driver havedifferent frequency response curves, the frequency division point may beselected within a frequency range. The frequency range may be above ½ ofthe upper limiting frequency of the low-frequency acoustic driver andbelow 2 times of the lower limiting frequency of the high-frequencyacoustic driver. In some embodiments, the frequency division point maybe selected in a frequency range above ⅓ of the upper limiting frequencyof the low-frequency acoustic driver and below 1.5 times of the lowerlimiting frequency of the high-frequency acoustic driver. In someembodiments, in the overlapping frequency range, the positionalrelationship between point sources may also affect the volume of thesound produced by the acoustic output apparatus in the near field andthe far field. More details may be found in International applicationNo. PCT/CN2019/130886, filed on Dec. 31, 2019, the entire contents ofwhich are hereby incorporated by reference.

The signal processor 820 and the signal processor 830 may furtherprocess a frequency-divided signal to meet the requirements of soundoutput. In some embodiments, the signal processor 820 and/or the signalprocessor 830 may include one or more signal processing components. Forexample, the signal processing components(s) may include, but notlimited to, an amplifier, an amplitude modulator, a phase modulator, adelayer, a dynamic gain controller, or the like, or any combinationthereof. Merely by way of example, the processing of a sound signal bythe signal processor 820 and/or the signal processor 830 may includeadjusting the amplitude of a portion of the sound signal that has aspecific frequency. In some embodiments, if the first frequency rangeand the second frequency range overlap, the signal processors 820 and830 may adjust the intensity of a portion of a sound signal that has thefrequency in the overlapping frequency range (for example, reduce theamplitude of the portion that has the frequency in the overlappingfrequency range). This may avoid that in a final sound outputted byacoustic output apparatus, the portion that corresponds to theoverlapping frequency range may have an excessive volume caused by thesuperposition of multiple sound signals.

After being processed by the signal processors 820 or 830, thefrequency-divided signals 1 and 2 may be transmitted to the acousticdrivers 840 and 850, respectively. In some embodiments, the processedfrequency-divided signal transmitted into the acoustic driver 840 may bea sound signal having a lower frequency range (e.g., the first frequencyrange). Therefore, the acoustic driver 840 may also be referred to as alow-frequency acoustic driver. The processed frequency-dividedtransmitted into the acoustic driver 850 may be a sound signal having ahigher frequency range (e.g., the second frequency range). Therefore,the acoustic driver 850 may also be referred to as a high-frequencyacoustic driver. The acoustic driver 840 and the acoustic driver 850 mayconvert sound signals into a low-frequency sound and a high-frequencysound, respectively, then propagate the converted signals outwards.

In some embodiments, the acoustic driver 840 may be acoustically coupledto at least two first sound guiding holes. For example, the acousticdriver 840 may be acoustically coupled to the two first sound guidingholes 847 via two acoustic routes 845. The acoustic driver 840 maypropagate sound through the at least two first sound guiding holes 847.The acoustic driver 850 may be acoustically coupled to at least twosecond sound guiding holes. For example, the acoustic driver 850 may beacoustically coupled to the two second sound guiding holes 857 via twoacoustic routes 855. The acoustic driver 850 may propagate sound throughthe at least two second sound guiding holes 857. A sound guiding holemay be a small hole formed on the acoustic output apparatus with aspecific opening and allowing sound to pass. The shape of a soundguiding hole may include but not limited to a circle shape, an ovalshape, a square shape, a trapezoid shape, a rounded quadrangle shape, atriangle shape, an irregular shape, or the like, or any combinationthereof. In addition, the number of the sound guiding holes connected tothe acoustic driver 840 or 850 may not be limited to two, which may bean arbitrary value instead, for example, three, four, six, or the like.

In some embodiments, in order to reduce the far-field leakage of theacoustic output apparatus 800, the acoustic driver 840 may be used tooutput low-frequency sounds with the same (or approximately the same)amplitude and opposite (or approximately opposite) phases via the atleast two first sound guiding holes. The acoustic driver 850 may be usedto output high-frequency sounds with the same (or approximately thesame) amplitude and opposite (or approximately opposite) phases via theat least two second sound guiding holes. In this way, the far-fieldleakage of low-frequency sounds (or high-frequency sounds) may bereduced according to the principle of acoustic interferencecancellation.

According to FIGS. 6 7A and 7B, considering that the wavelength of alow-frequency sound is longer than that of a high-frequency sound, andin order to reduce the interference cancellation of the sound in thenear field (for example, near the user's ear), the distance between thefirst sound guiding holes and the distance between the second soundguiding holes may have different values. For example, assuming thatthere is a first distance between the two first sound guiding holes anda second distance between the two second sound guiding holes, the firstdistance may be longer than the second distance. In some embodiments,the first distance and the second distance may be arbitrary values.Merely by way of example, the first distance may not be longer than 40mm, for example, in the range of 20 mm-40 mm. The second distance maynot be longer than 12 mm, and the first distance may be longer than thesecond distance. In some embodiments, the first distance may not beshorter than 12 mm. The second distance may be shorter than 7 mm, forexample, in the range of 3 mm-7 mm. In some embodiments, the firstdistance may be 30 mm, and the second distance may be 5 mm. As anotherexample, the first distance may be at least twice longer than the seconddistance. In some embodiments, the first distance may be at least threetimes longer than the second distance. In some embodiments, the firstdistance may be at least 5 times longer than the second distance.

As shown in FIG. 8, the acoustic driver 840 may include a transducer843. The transducer 843 may transmit a sound to the first sound guidinghole(s) 847 through the acoustic route 845. The acoustic driver 850 mayinclude a transducer 853. The transducer 853 may transmit a sound to thesecond sound guiding hole(s) 857 through the acoustic route 855. In someembodiments, the transducer may include, but not limited to, atransducer of a gas-conducting acoustic output apparatus, a transducerof a bone-conducting acoustic output apparatus, a hydroacoustictransducer, an ultrasonic transducer, or the like, or any combinationthereof. In some embodiments, the transducer may be of a moving coiltype, a moving iron type, a piezoelectric type, an electrostatic type,or a magneto strictive type, or the like, or any combination thereof.

In some embodiments, the acoustic drivers (such as the low-frequencyacoustic driver 840, the high-frequency acoustic driver 850) may includetransducers with different properties or different counts of tranducers.For example, each of the low-frequency acoustic driver 840 and thehigh-frequency acoustic driver 850 may include a transducer, and thetransducers of the frequency acoustic driver 840 and the high-frequencyacoustic driver 850 may have different frequency responsecharacteristics (such as a low-frequency speaker unit and ahigh-frequency speaker unit). As another example, the low-frequencyacoustic driver 840 may include two transducers 843 (such as twolow-frequency speaker units), and the high-frequency acoustic driver 850may include two transducers 853 (such as two high-frequency speakerunits).

In some embodiments, the acoustic output apparatus 800 may generatesounds with different frequency ranges by other means, for example, atransducer frequency division, an acoustic route frequency division, orthe like. When the acoustic output apparatus 800 uses a transducer or anacoustic route to divide a sound, the electronic frequency divisionmodule 810 (e.g., the part inside the dotted frame in FIG. 8) may beomitted. The source signal may be input to the acoustic driver 840 andthe acoustic driver 850, respectively.

In some embodiments, the acoustic output apparatus 800 may use aplurality of transducers to achieve signal frequency division. Forexample, the acoustic driver 840 and the acoustic driver 850 may convertthe inputted source signal into a low-frequency signal and ahigh-frequency signal, respectively. Specifically, through thetransducer 843 (such as a low-frequency speaker), the low-frequencyacoustic driver 840 may convert the source signal into the low-frequencysound having a low-frequency component. The low-frequency sound may betransmitted to at least two first sound guiding holes 847 along at leasttwo different acoustic routes 845. Then the low-frequency sound may bepropagated outwards through the first sound guiding holes 847. Throughthe transducer 853 (such as a high-frequency speaker), thehigh-frequency acoustic driver 850 may convert the source signal intothe high-frequency sound having a high-frequency component. Thehigh-frequency sound may be transmitted to at least two second soundguiding holes 857 along at least two different acoustic routes 855. Thenthe high-frequency sound may be propagated outwards through the secondsound guiding holes 857.

In some alternative embodiments, an acoustic route (e.g., the acousticroutes 845 and the acoustic routes 855) connecting a transducer and asound guiding hole may affect the nature of the transmitted sound. Forexample, an acoustic route may attenuate or change the phase of thetransmitted sound to some extent. In some embodiments, the acousticroute may include a sound tube, a sound cavity, a resonance cavity, asound hole, a sound slit, a tuning net, or the like, or any combinationthereof. In some embodiments, the acoustic route may include an acousticresistance material, which may have a specific acoustic impedance. Forexample, the acoustic impedance may be in the range of SMKS Rayleigh to500MKS Rayleigh. Exemplary acoustic resistance materials may include butnot limited to plastic, textile, metal, permeable material, wovenmaterial, screen material or mesh material, porous material, particulatematerial, polymer material, or the like, or any combination thereof. Bysetting acoustic routes of different acoustic impedances, the soundsoutput of different transducers may be acoustically filtered. In thiscase, the sounds output through different acoustic routes have differentfrequency components.

In some embodiments, the acoustic output apparatus 800 may utilize aplurality of acoustic routes to achieve signal frequency division.Specifically, the source signal may be inputted into a specific acousticdriver and converted into a sound including high and low-frequencycomponents. The sound may be propagated along an acoustic route having aspecific frequency selection characteristic. For example, the sound maybe propagated along an acoustic route with a low-pass characteristic toa corresponding sound guiding hole to output a low-frequency sound. Inthis process, the high-frequency component of the sound may be absorbedor attenuated by the acoustic route with a low-pass characteristic.Similarly, the sound signal may be propagated along an acoustic routewith a high-pass characteristic to the corresponding sound guiding holeto output a high-frequency sound. In this process, the low-frequencycomponent of the sound may be absorbed or attenuated by the acousticroute with the high-pass characteristic.

In some embodiments, the controller in the acoustic output apparatus 800may cause the low-frequency acoustic driver 840 to output a sound in thefirst frequency range (i.e., a low-frequency sound), and cause thehigh-frequency acoustic driver 850 to output a sound in the secondfrequency range (i.e., a high-frequency sound). In some embodiments, theacoustic output apparatus 800 may also include a supporting structure.The supporting structure may be used to carry an acoustic driver (suchas the high-frequency acoustic driver 850, the low-frequency acousticdriver 840), so that the acoustic driver may be positioned away from theuser's ear. In some embodiments, the sound guiding hole(s) acousticallycoupled with the high-frequency acoustic driver 850 may be locatedcloser to an expected position of the user's ears (for example, the earcanal entrance), while the sound guiding hole(s) acoustically coupledwith the low-frequency acoustic driver 840 may be located further awayfrom the expected position. In some embodiments, the supportingstructure may be used to package the acoustic driver. For example, thesupporting structure may include a casing made of various materials suchas plastic, metal, and tape. The casing may encapsulate the acousticdriver and form a front chamber and a rear chamber corresponding to theacoustic driver. The front chamber may be acoustically coupled to one ofthe at least two sound guiding holes corresponding to the acousticdriver. The rear chamber may be acoustically coupled to the other of theat least two sound guiding holes corresponding to the acoustic driver.For example, the front chamber of the low-frequency acoustic driver 840may be acoustically coupled to one of the at least two first soundguiding holes 847. The rear chamber of the low-frequency acoustic driver840 may be acoustically coupled to the other of the at least two firstsound guiding holes 847. The front chamber of the high-frequencyacoustic driver 850 may be acoustically coupled to one of the at leasttwo second sound guiding holes 857. The rear chamber of thehigh-frequency acoustic driver 850 may be acoustically coupled to theother of the at least two second sound guiding holes 857. In someembodiments, a sound guiding hole (such as the first sound guidinghole(s) 847 and the second sound guiding hole(s) 857) may be disposed onthe casing.

The above description of the acoustic output apparatus 800 may be merelyprovided by way of example. Those skilled in the art may makeadjustments and changes to the structure, quantity, etc., of theacoustic driver, which is not limiting in the present disclosure. Insome embodiments, the acoustic output apparatus 800 may include anynumber of the acoustic drivers. For example, the acoustic outputapparatus 800 may include two groups of the high-frequency acousticdrivers 850 and two groups of the low-frequency acoustic drivers 840, orone group of the high-frequency acoustic drives 850 and two groups ofthe low-frequency acoustic drivers 840, and thesehigh-frequency/low-frequency drivers may be used to generate a sound ina specific frequency range, respectively. As another example, theacoustic driver 840 and/or the acoustic driver 850 may include anadditional signal processor. The signal processor may have the samestructural component as or different structural component from thesignal processor 820 or 830.

It should be noted that the acoustic output apparatus and its modulesshown in FIG. 8 may be implemented in various ways. For example, in someembodiments, the system and the modules may be implemented by hardware,software, or a combination of both. The hardware may be implemented by adedicated logic. The software may be stored in a storage which may beexecuted by a suitable instruction execution system, for example, amicroprocessor or a dedicated design hardware. It will be appreciated bythose skilled in the art that the above methods and systems may beimplemented by computer-executable instructions and/or embedded incontrol codes of a processor. For example, the control codes may beprovided by a medium such as a disk, a CD or a DVD-ROM, a programmablememory device, such as read-only memory (e.g., firmware), or a datacarrier such as an optical or electric signal carrier. The system andthe modules in the present disclosure may be implemented not only by ahardware circuit in a programmable hardware device in an ultra largescale integrated circuit, a gate array chip, a semiconductor such alogic chip or a transistor, a field programmable gate array, or aprogrammable logic device. The system and the modules in the presentdisclosure may also be implemented by a software to be performed byvarious processors, and further also by a combination of hardware andsoftware (e.g., firmware).

It should be noted that the above description of the acoustic outputapparatus 800 and its components is only for convenience of description,and not intended to limit the scope of the present disclosure. It may beunderstood that, for those skilled in the art, after understanding theprinciple of the apparatus, it is possible to combine each unit or forma substructure to connect with other units arbitrarily without departingfrom this principle. For example, the electronic frequency divisionmodule 810 may be omitted, and the frequency division of the sourcesignal may be implemented by the internal structure of the low-frequencyacoustic driver 840 and/or the high-frequency acoustic driver 850. Asanother example, the signal processor 820 or 830 may be a partindependent of the electronic frequency division module 810. Thosemodifications may fall within the scope of the present disclosure.

FIGS. 9A and 9B are schematic diagrams illustrating exemplary acousticoutput apparatuses according to some embodiments of the presentdisclosure. For the purpose of illustration, sounds outputted bydifferent sound guiding holes coupled with a same transducer may bedescribed as an example. In FIGS. 9A and 9B, each transducer may have afront side and a rear side, and a front chamber and a rear chamber mayexist on the front and rear side of the transducer, respectively. Insome embodiments, these structures may have the same or approximatelythe same equivalent acoustic impedance, such that the transducer may beloaded symmetrically. The symmetrical load of the transducer may formsound sources satisfying an amplitude and phase relationship atdifferent sound guiding holes (such as the “two point sources” having asame amplitude and opposite phases as described above), such that aspecific sound field may be formed in the high-frequency range and/orthe low-frequency range (for example, the near-field sound may beenhanced and the far-field leakage may be suppressed).

As shown in FIGS. 9A and 9B, an acoustic driver (for example, theacoustic driver 910 or 920) may include transducers, and acoustic routesand sound guiding holes connected to the transducers. In order todescribe an actual application scenario of the acoustic output apparatusmore clearly, a position of a user's ear E is shown in FIGS. 9A and 9Bfor explanation. FIG. 9A illustrates an application scenario of theacoustic driver 910. The acoustic driver 910 may include a transducer943 (or referred to as a low-frequency acoustic driver), and thetransducer 943 may be coupled with two first sound guiding holes 947through an acoustic route 945. FIG. 9B illustrates an applicationscenario of the acoustic driver 920. The acoustic driver 920 may includea transducer 953 (or referred to as a high-frequency acoustic driver),and the transducer 953 may be coupled with two second sound guidingholes 957 through an acoustic route 955.

The transducer 943 or 953 may vibrate under the driving of an electricsignal, and the vibration may generate sounds with equal amplitudes andopposite phases (180 degrees inversion). The type of the transducer mayinclude, but not limited to, an air conduction speaker, a boneconduction speaker, a hydroacoustic transducer, an ultrasonictransducer, or the like, or any combination thereof. The transducer maybe of a moving coil type, a moving iron type, a piezoelectric type, anelectrostatic type, a magneto strictive type, or the like, or anycombination thereof. In some embodiments, the transducer 943 or 953 mayinclude a vibration diaphragm, which may vibrate when driven by anelectrical signal, and the front and rear sides of the vibrationdiaphragm may simultaneously output a normal-phase sound and areverse-phase sound. In FIGS. 9A and 9B, “+” and “−” may be used torepresent sounds with different phases, wherein “+” may represent anormal-phase sound, and “−” may represent a reverse-phase sound.

In some embodiments, a transducer may be encapsulated by a casing of asupporting structure, and the interior of the casing may be providedwith sound channels connected to the front and rear sides of thetransducer, respectively, thereby forming an acoustic route. Forexample, a front cavity of the transducer 943 may be coupled to one ofthe two first sound guiding holes 947 through a first acoustic route(i.e., a half of the acoustic route 945), and a rear cavity of thetransducer 943 may acoustically be coupled to the other sound guidinghole of the two first sound guiding holes 947 through a second acousticroute (i.e., the other half of the acoustic route 945). A normal-phasesound and a reverse-phase sound output from the transducer 943 may beoutput from the two first sound guiding holes 947, respectively. Asanother example, a front cavity of the transducer 953 may be coupled toone of the two sound guiding holes 957 through a third acoustic route(i.e., half of the acoustic route 955), and a rear cavity of thetransducer 953 may be coupled to another sound guiding hole of the twosecond sound guiding holes 957 through a fourth acoustic route (i.e.,the other half of the acoustic route 955). A normal-phase sound and areverse-phase sound output from the transducer 953 may be output fromthe two second sound guiding holes 957, respectively.

In some embodiments, an acoustic route may affect the nature of thetransmitted sound. For example, an acoustic route may attenuate orchange the phase of the transmitted sound to some extent. In someembodiments, the acoustic route may include one or more of a sound tube,a sound cavity, a resonance cavity, a sound hole, a sound slit, a tuningnet, or the like, or any combination thereof. In some embodiments, theacoustic route may include an acoustic resistance material, which mayhave a specific acoustic impedance. For example, the acoustic impedancemay be in the range of SMKS Rayleigh to 500MKS Rayleigh. In someembodiments, the acoustic resistance material may include but notlimited to plastics, textiles, metals, permeable materials, wovenmaterials, screen materials, and mesh materials, or the like, or anycombination thereof. In some embodiments, in order to prevent the soundtransmitted by the acoustic driver's front chamber and rear chamber frombeing differently disturbed, the front chamber and rear chambercorresponding to the acoustic driver may have the approximately sameequivalent acoustic impedance. Additionally, sound guiding holes withthe same acoustic resistance material, the same size and/or shape, etc.,may be used.

The distance between the two first sound guiding holes 947 of thelow-frequency acoustic driver may be expressed as d1 (i.e., the firstdistance). The distance between the two second sound guiding holes 957of the high-frequency acoustic driver may be expressed as d2 (i.e., thesecond distance). By setting the distances d1 and d2, a higher soundvolume output in the low-frequency band and a stronger ability to reducethe sound leakage in the high-frequency band may be achieved. Forexample, the distance between the two first sound guiding holes 947 isgreater than the distance between the two second sound guiding holes 957(i.e., d1>d2).

In some embodiments, the transducer 943 and the transducer 953 may behoused together in a housing of an acoustic output apparatus, and beplaced in isolation in a structure of the housing.

In some embodiments, the acoustic output apparatus may include multiplesets of high-frequency acoustic drivers and low-frequency acousticdrivers. For example, the acoustic output apparatus may include a set ofhigh-frequency acoustic drivers and a set of low-frequency acousticdrivers for simultaneously outputting sound to the left and/or rightears. As another example, the acoustic output apparatus may include twosets of high-frequency acoustic drivers and two sets of low-frequencyacoustic drivers, wherein one set of high-frequency acoustic drivers andone set of low-frequency acoustic drivers may be used to output sound toa user's left ear, and the other set of high-frequency acoustic driversand the other set of low-frequency acoustic drivers may be used tooutput sound to a user's right ear.

In some embodiments, the high-frequency acoustic driver and thelow-frequency acoustic driver may have different powers. In someembodiments, the low-frequency acoustic driver may have a first power,the high-frequency acoustic driver may have a second power, and thefirst power may be greater than the second power. In some embodiments,the first power and the second power may be arbitrary values.

FIGS. 10A, 10B, and 100 are schematic diagrams illustrating sound outputscenarios according to some embodiments of the present disclosure.

In some embodiments, the acoustic output apparatus may generate soundsin the same frequency range through two or more transducers, and thesounds may propagate outwards through different sound guiding holes. Insome embodiments, different transducers may be controlled by the samecontroller or different controllers, respectively, and may producesounds that satisfy a certain phase and amplitude condition (forexample, sounds with the same amplitude but opposite phases, sounds withdifferent amplitudes and opposite phases, etc.). For example, acontroller may make the electrical signals input into two low-frequencytransducers of an acoustic driver have the same amplitude and oppositephases. In this way, the two low-frequency transducers may outputlow-frequency sounds with the same amplitude but opposite phases.

Specifically, the two transducers in an acoustic driver (such as alow-frequency acoustic driver 1010 or a high-frequency acoustic driver1020) may be arranged side by side in an acoustic output apparatus, oneof which may be used to output a normal-phase sound, and the other maybe used to output a reverse-phase sound. As shown in FIG. 10A, theacoustic driver 1010 may include two transducers 1043, two acousticroutes 1045, and two first sound guiding holes 1047. As shown in FIG.10B, the acoustic driver 1050 may include two transducers 1053, twoacoustic routes 1055, and two second sound guiding holes 1057. Driven byelectrical signals with opposite phases, the two transducers 1043 maygenerate a set of low-frequency sounds with opposite phases (180 degreesinversion). One of the two transducers 1043 (such as the transducerlocated below) may output a normal-phase sound, and the other (such asthe transducer located above) may output a reverse-phase sound. The twolow-frequency sounds with opposite phases may be transmitted to the twofirst sound guiding holes 1047 along the two acoustic routes 1045,respectively, and propagate outwards through the two first sound guidingholes 1047. Similarly, driven by electrical signals with oppositephases, the two transducers 1053 may generate a set of high-frequencysounds with opposite phases (180 degrees inversion). One of the twotransducers 1053 (such as the transducer located below) may output anormal-phase high-frequency sound, and the other (such as the transducerlocated above) may output a reverse-phase high-frequency sound. Thehigh-frequency sounds with opposite phases may be transmitted to the twosecond sound guiding holes 1057 along the two acoustic routes 1055,respectively, and propagate outwards through the two second soundguiding holes 1057.

In some embodiments, the two transducers in an acoustic driver (forexample, the low-frequency acoustic driver 1043 and the high-frequencyacoustic driver 1053) may be arranged relatively close to each otheralong a straight line, and one of them may be used to output anormal-phase sound and the other may be used to output a reverse-phasesound.

As shown in FIG. 100, the left side may be the acoustic driver 1010, andthe right side may be the acoustic driver 1020. The two transducers 1043of the acoustic driver 1010 may generate a set of low-frequency soundsof equal amplitude and opposite phases under the control of thecontroller, respectively. One of the transducers 1043 may output anormal-phase low-frequency sound, and transmit the normal-phaselow-frequency sound along a first acoustic route to a first soundguiding hole 1047. The other transducer 1043 may output a reverse-phaselow-frequency sound, and transmit the reverse-phase low-frequency soundalong a second acoustic route to another first sound guiding hole 1047.The two transducers 1053 of the acoustic driver 1020 may generatehigh-frequency sounds of equal amplitude and opposite phases under thecontrol of the controller, respectively. One of the transducers 1053 mayoutput a normal-phase high-frequency sound, and transmit thenormal-phase high-frequency sound along a third acoustic route to asecond sound guiding hole 1057. The other transducer 1053 may output areverse-phase high-frequency sound, and transmit the reverse-phasehigh-frequency sound along a fourth acoustic route to another secondsound guiding hole 1057.

In some embodiments, the transducer 1043 and/or the transducer 1053 maybe of various suitable types. For example, the transducer 1043 and thetransducer 1053 may be dynamic coil speakers, which may have thecharacteristics of a high sensitivity in low-frequency, a deep lowfrequency depth, and a small distortion. As another example, thetransducer 1043 and the transducer 1053 may be moving iron speakers,which may have the characteristics of a small size, a high sensitivity,and a large high-frequency range. As another example, the transducers1043 and 1053 may be air-conducted speakers or bone-conducted speakers.As yet another example, the transducer 1043 and the transducer 1053 maybe balanced armature speakers. In some embodiments, the transducer 1043and the transducer 1053 may be of different types. For example, thetransducer 1043 may be a moving iron speaker, and the transducer 1053may be a moving coil speaker. As another example, the transducer 1043may be a dynamic coil speaker, and the transducer 1053 may be a movingiron speaker.

In FIGS. 10A-10C, the distance between the two point sources of theacoustic driver 1010 may be d1, the distance between the two pointsources of the acoustic driver 1020 may be d2, and d1 may be greaterthan d2. As shown in FIG. 100, the listening position (that is, theposition of the ear canal when the user wears an acoustic outputapparatus) may be approximately located on a line of a set of two pointsources. In some embodiments, the listening position may be located atany suitable position. For example, the listening position may belocated on a circle centered on the center point of the two pointsources. As another example, the listening position may be on the sameside of the two lines of the two sets of point sources.

It may be understood that the simplified structure of the acousticoutput apparatus shown in FIGS. 10A-10C may be merely by way of example,which may be not a limitation for the present disclosure. In someembodiments, the acoustic output apparatus may include a supportingstructure, a controller, a signal processor, or the like, or anycombination thereof.

FIGS. 11A and 11B are schematic diagrams illustrating an acoustic outputapparatus according to some embodiments of the present disclosure.

In some embodiments, acoustic drivers (e.g., acoustic drivers 1043 or1053) may include multiple narrow-band speakers. As shown in FIG. 11A,the acoustic output apparatus may include a plurality of narrow-bandspeaker units and a signal processing module. On the left or right sideof the user, the acoustic output apparatus may include n groups,narrow-band speaker units, respectively. Each group of narrow-bandspeaker units may have different frequency response curves, and thefrequency response of each group may be complementary and collectivelycover the audible sound frequency band. A narrow-band speaker unit usedherein may be an acoustic driver with a narrower frequency responserange than a low-frequency acoustic driver and/or a high-frequencyacoustic driver. Taking the speaker units located on the left side ofthe user as shown in FIG. 11A as an example: A1˜An and B1˜Bn form ngroups of two point sources. When a same electrical signal is input,each two point sources may generate sounds with different frequencyranges. By setting the distance do of each two point sources, thenear-field and far-field sound of each frequency band may be adjusted.For example, in order to enhance the volume of near-field sound andreduce the volume of far-field leakage, the distance between a pair oftwo point sources corresponding to a high frequency may be less than thedistance between a pair of two point sources corresponding to a lowfrequency.

In some embodiments, the signal processing module may include anEqualizer (EQ) processing module and a Digital Signal Processor (DSP)processing module. The signal processing module may be used to implementsignal equalization and other digital signal processing algorithms (suchas amplitude modulation and phase modulation). The processed signal maybe connected to a corresponding acoustic driver (for example, anarrow-band speaker unit) to output a sound. Preferably, a narrow-bandspeaker unit may be a dynamic coil speaker or a moving iron speaker. Insome embodiments, the narrow-band speaker unit may be a balancedarmature speaker. Two point sources may be constructed using twobalanced armature speakers, and the sound output from the two speakersmay be in opposite phases.

In some embodiments, an acoustic driver (such as acoustic drivers 840,850, 1040 or 1050) may include multiple sets of full-band speakers. Asshown in FIG. 11B, the acoustic output apparatus may include a pluralityof sets of full-band speaker units and a signal processing module. Onthe left or right side of the user, the acoustic output apparatus mayinclude n groups full-band speaker units, respectively. Each full-bandspeaker unit may have the same or similar frequency response curve, andmay cover a wide frequency range.

Taking the speaker units located on the left side of the user as shownin FIG. 11B as an example: A1˜An and B1˜Bn form n groups of two pointsources. The difference between FIGS. 11A and 11B may be that the signalprocessing module in FIG. 11B may include at least one set of filtersfor performing frequency division on the sound source signal to generateelectric signals corresponding to different frequency ranges, and theelectric signals corresponding to different frequency ranges may beinput into each group of full-band speaker units. In this way, eachgroup of speaker units (similar to the two point sources) may producesounds with different frequency ranges separately.

FIGS. 12A-12C are schematic diagrams illustrating an acoustic routeaccording to some embodiments of the present disclosure.

As described above, an acoustic filtering structure may be constructedby setting structures such as a sound tube, a sound cavity, and a soundresistance in an acoustic route to achieve frequency division of sound.FIGS. 12A-12C show schematic structural diagrams of frequency divisionof a sound signal using an acoustic route. It should be noted that FIGS.12A-12C may be examples of setting the acoustic route when using theacoustic route to perform frequency division on the sound signal, andmay not be a limitation on the present disclosure.

As shown in FIG. 12A, an acoustic route may include one or more groupsof lumen structures connected in series, and an acoustic resistancematerial may be provided in the lumen structures to adjust the acousticimpedance of the entire structure to achieve a filtering effect. In someembodiments, a band-pass filtering or a low-pass filtering may beperformed on the sound by adjusting the size of the lumen structuresand/or the acoustic resistance material to achieve frequency division ofthe sound. As shown in FIG. 12B, a structure with one or more sets ofresonant cavities (for example, Helmholtz cavity) may be constructed ona branch of the acoustic route, and the filtering effect may be achievedby adjusting the size of each resonant cavity and the acousticresistance material. As shown in FIG. 12C, a combination of a lumenstructure and a resonant cavity (for example, a Helmholtz cavity) may beconstructed in an acoustic route, and a filtering effect may be achievedby adjusting the size of the lumen structure and/or a resonant cavity,and/or the acoustic resistance material.

FIG. 13 shows a curve of a sound leakage of an acoustic output apparatus(for example, the acoustic output apparatus 800) under the action of twosets of two point sources (a set of high-frequency two point sources anda set of low-frequency two point sources). The frequency division pointsof the two sets of two point sources may be around 700 Hz.

A normalization parameter a may be used to evaluate the volume of theleaked sound (descriptions of a may be found in Equation (4)). As shownin FIG. 13, compared with a single point source, the two sets of twopoint sources may have a stronger ability to reduce sound leakage. Inaddition, compared with the acoustic output apparatus provided with onlyone set of two point sources, the two sets of two point sources mayoutput high-frequency sounds and low-frequency sounds, separately. Thedistance between the low-frequency two point sources may be greater thanthat of the high-frequency two point sources. In the low-frequencyrange, by setting a larger distance (d1) between the low frequency twopoint sources, the increase in the volume of the near-field sound may begreater than the increase in the volume of the far-field leakage, whichmay achieve a higher volume of the near-field sound output in thelow-frequency band. At the same time, in the low-frequency range,because that the sound leakage of the low frequency two point sources isvery small, increasing the distance d1 may slightly increase the soundleakage. In the high-frequency range, by setting a small distance (d2)between the high frequency two point sources, the problem that thecutoff frequency of high-frequency sound leakage reduction is too lowand the audio band of the sound leakage reduction is too narrow may beovercame. Therefore, by setting the distance d1 and/or the distance d2,the acoustic output apparatus provided in the embodiments of the presentdisclosure may obtain a stronger sound leakage suppressing capabilitythan an acoustic output apparatus having a single point source or asingle set of two point sources.

In some embodiments, affected by factors such as the filtercharacteristic of a circuit, the frequency characteristic of atransducer, and the frequency characteristic of an acoustic route, theactual low-frequency and high-frequency sounds of the acoustic outputapparatus may differ from those shown in FIG. 13. In addition,low-frequency and high-frequency sounds may have a certain overlap(aliasing) in the frequency band near the frequency division point,causing the total sound leakage reduction of the acoustic outputapparatus not have a mutation at the frequency division point as shownin FIG. 13. Instead, there may be a gradient and/or a transition in thefrequency band near the frequency division point, as shown by a thinsolid line in FIG. 13. It may be understood that these differences maynot affect the overall leakage reduction effect of the acoustic outputapparatus provided by the embodiments of the present disclosure.

According to FIGS. 8 to 13 and the related descriptions, the acousticoutput apparatus provided by the present disclosure may be used tooutput sounds in different frequency bands by setting high-frequency twopoint sources and low-frequency two point sources, thereby achieving abetter acoustic output effect. In addition, by setting different sets oftwo point sources with different distances, the acoustic outputapparatus may have a stronger capability to reduce the sound leakage ina high frequency band, and meet the requirements of an open acousticoutput apparatus.

In some alternative embodiments, an acoustic output apparatus mayinclude at least one acoustic driver, and the sound generated by the atleast one acoustic driver may propagate outwards through at least twosound guiding holes coupled with the at least one acoustic driver. Insome embodiments, the acoustic output apparatus may be provided with abaffle structure, so that the at least two sound guiding holes may bedistributed on two sides of the baffle. In some embodiments, the atleast two sound guiding holes may be distributed on both sides of theuser's auricle. At this time, the auricle may serve as a baffle thatseparates the at least two sound guiding holes, so that the at least twosound guiding holes may have different acoustic routes to the user's earcanal. More descriptions of two point sources and a baffle may be foundin International applications No. PCT/CN2019/130921 and No.PCT/CN2019/130942, both filed on Dec. 31, 2019, the entire contents ofeach of which are hereby incorporated by reference in the presentdisclosure.

FIG. 14 is a schematic diagram illustrating another exemplary acousticoutput apparatus 1400 according to some embodiments of the presentdisclosure. As shown in FIG. 14, the acoustic output apparatus 1400 mayinclude a supporting structure 1410 and an acoustic driver 1420 mountedwithin the supporting structure 1410. In some embodiments, the acousticoutput apparatus 1400 may be worn on the user's body (for example, thehuman body's head, neck, or upper torso) through the supportingstructure 1410. At the same time, the supporting structure 1410 and theacoustic driver 1420 may approach but not block the ear canal, so thatthe user's ear may remain open, thus the user may hear both the soundoutput from the acoustic output apparatus 1400 and the sound of theexternal environment. For example, the acoustic output apparatus 1400may be arranged around or partially around the user's ear, and transmitsounds by means of air conduction or bone conduction.

The supporting structure 1410 may be used to be worn on the user's bodyand include one or more acoustic drivers 1420. In some embodiments, thesupporting structure 1410 may have an enclosed shell structure with ahollow interior, and the one or more acoustic drivers 1420 may belocated inside the supporting structure 1410. In some embodiments, theacoustic output apparatus 1400 may be combined with a product, such asglasses, a headset, a display apparatus, an AR/VR helmet, etc. In thiscase, the supporting structure 1410 may be fixed near the user's ear ina hanging or clamping manner. In some alternative embodiments, a hookmay be provided on the supporting structure 1410, and the shape of thehook may match the shape of the user's auricle, so that the acousticoutput apparatus 1400 may be independently worn on the user's earthrough the hook. The acoustic output apparatus 1400 may communicatewith a signal source (for example, a computer, a mobile phone, or othermobile devices) in a wired or wireless manner (for example, Bluetooth).For example, the acoustic output apparatus 1400 at the left and rightears may be directly in communication connection with the signal sourcein a wireless manner. As another example, the acoustic output apparatus1400 at the left and right ears may include a first output apparatus anda second output apparatus. The first output apparatus may be incommunication connection with the signal source, and the second outputapparatus may be wirelessly connected with the first output apparatus ina wireless manner. The audio output of the first output apparatus andthe second output apparatus may be synchronized through one or moresynchronization signals. A wireless connection disclosed herein mayinclude but not limited to a Bluetooth, a local area network, a widearea network, a wireless personal area network, a near fieldcommunication, or the like, or any combination thereof.

In some embodiments, the supporting structure 1410 may have a shellstructure with a shape suitable for human ears, for example, a circularring, an oval, a polygonal (regular or irregular), a U-shape, a V-shape,a semi-circle, so that the supporting structure 1410 may be directlyhooked at the user's ear. In some embodiments, the supporting structure1410 may include one or more fixed structures. The fixed structure(s)may include an ear hook, a head strip, or an elastic band, so that theacoustic output apparatus 1400 may be better fixed on the user,preventing the acoustic output apparatus 1400 from falling down. Merelyby way of example, the elastic band may be a headband to be worn aroundthe head region. As another example, the elastic band may be a neckbandto be worn around the neck/shoulder region. In some embodiments, theelastic band may be a continuous band and be elastically stretched to beworn on the user's head. In the meanwhile, the elastic band may alsoexert pressure on the user's head so that the acoustic output apparatus1400 may be fixed to a specific position on the user's head. In someembodiments, the elastic band may be a discontinuous band. For example,the elastic band may include a rigid portion and a flexible portion. Therigid portion may be made of a rigid material (for example, plastic ormetal), and the rigid portion may be fixed to the supporting structure1410 of the acoustic output apparatus 1400 by a physical connection. Theflexible portion may be made of an elastic material (for example, cloth,composite, or/and neoprene).

In some embodiments, when the user wears the acoustic output apparatus1400, the supporting structure 1410 may be located above or below theauricle. The supporting structure 1410 may be provided with a soundguiding hole 1411 and a sound guiding hole 1412 for transmitting sound.In some embodiments, the sound guiding hole 1411 and the sound guidinghole 1412 may be located on both sides of the user's auricle,respectively, and the acoustic driver 1420 may output sounds through thesound guiding hole 1411 and the sound guiding hole 1412.

The acoustic driver 1420 may be a component that may receive anelectrical signal, and convert the electrical signal into a sound signalfor output. In some embodiments, in terms of frequency, the type of theacoustic driver 1420 may include a low-frequency acoustic driver, ahigh-frequency acoustic driver, or a full-frequency acoustic driver, orany combination thereof. In some embodiments, the acoustic driver 1420may include a moving coil, a moving iron, a piezoelectric, anelectrostatic, a magnetostrictive driver, or the like, or a combinationthereof.

In some embodiments, the acoustic driver 1420 may include a vibrationdiaphragm. When the vibration diaphragm vibrates, sounds may betransmitted from the front and rear sides of the vibration diaphragm,respectively. In some embodiments, the front side of the vibrationdiaphragm in the supporting structure 1410 may be provided with a frontchamber 1413 for transmitting sound. The front chamber 1413 may beacoustically coupled with the sound guiding hole 1411. The sound on thefront side of the vibration diaphragm may be outputted from the soundguiding hole 1411 through the front chamber 1413. The rear side of thevibration diaphragm in the supporting structure 1410 may be providedwith a rear chamber 1414 for transmitting sound. The rear chamber 1414may be acoustically coupled with the sound guiding hole 1412. The soundon the rear side of the vibration diaphragm may be outputted from thesound guiding hole 1412 through the rear chamber 1414. It should benoted that, when the vibration diaphragm is vibrating, the front sideand the rear side of the vibration diaphragm may simultaneously generatesounds with opposite phases. After passing through the front chamber1413 and rear chamber 1414, respectively, the sounds may propagateoutward from the sound guiding hole 1411 and the sound guiding hole1412, respectively. In some embodiments, by adjusting the structure ofthe front chamber 1413 and the rear chamber 1414, the sounds output bythe acoustic driver 1420 at the sound guiding hole 1411 and the soundguiding hole 1412 may meet specific conditions. For example, bydesigning the lengths of the front chamber 1413 and the rear chamber1414, the sound guiding hole 1411 and the sound guiding hole 1412 mayoutput sounds with a specific phase relationship (for example, oppositephases). Therefore, the problems including a small volume of the soundheard by the user in the near field of the acoustic output apparatus1400 and a large sound leakage in the far field of the acoustic outputapparatus 1400 may be effectively resolved.

In some alternative embodiments, the acoustic driver 1420 may alsoinclude a plurality of vibration diaphragms (e.g., two vibrationdiaphragms). Each of the plurality of vibration diaphragms may vibrateto generate a sound, which may pass through a cavity connected to thevibration diaphragm in the supporting structure, and output fromcorresponding sound guiding hole(s). The plurality of vibrationdiaphragms may be controlled by the same controller or differentcontrollers and generate sounds that satisfy certain phase and amplitudeconditions (for example, sounds of the same amplitude but oppositephases, sounds of different amplitudes and opposite phases, etc.).

As mentioned above, with a certain sound frequency, as the distancebetween two point sources increases, the volume of the sound heard bythe user and the volume of the leaked sound corresponding to the twopoint sources may increase. For a clearer description, the relationshipbetween volume of the sound heard by the user, the volume of soundleakage, and the point source distance d may be further explained inconnection with FIGS. 15 through 17.

FIG. 15 is a schematic diagram illustrating two point sources and alistening position according to some embodiments of the presentdisclosure. As shown in FIG. 15, a point source a1 and a point source a2may be on a same side of the listening position. The point source a1 maybe closer to the listening position, and the point source a1 and thepoint source a2 may output sounds with the same amplitude but oppositephases.

FIG. 16 is a graph illustrating a variation of the volume of the soundheard by the user of two point sources with different distances as afunction of a frequency of sound according to some embodiments of thepresent disclosure. The abscissa may represent the frequency (f) of thesound output by the two point sources (denoted as a1 and a2), and theunit may be hertz (Hz). The ordinate may represent the volume of thesound, and the unit may be decibel (dB). As shown in FIG. 16, as thedistance between the point source a1 and the point source a2 graduallyincreases (for example, from d to 10 d), the sound volume at thelistening position may gradually increase. That is, as the distancebetween the point source a1 and the point source a2 increases, thedifference in sound pressure amplitude (i.e., sound pressure difference)between the two sounds reaching the listening position may becomelarger, making the sound cancellation effect weaker, which may increasethe sound volume at the listening position. However, due to theexistence of sound cancellation, the sound volume at the listeningposition may still be less than the sound volume generated by a singlepoint source at a same position in the low and middle frequency band(for example, a frequency of less than 1000 Hz). However, in thehigh-frequency band (for example, a frequency close to 10000 Hz), due tothe decrease in the wavelength of the sound, mutual enhancement of thesound may appear, making the sound generated by the two point sourceslouder than that of the single point source. In some embodiments, asound pressure may refer to the pressure generated by the sound throughthe vibration of the air.

In some embodiments, by increasing the distance between the two pointsources (for example, the point source a1 and the point source a2), thesound volume at the listening position may be increased. But as thedistance increases, the sound cancellation of the two point sources maybecome weaker, which may lead to an increase of the far-field soundleakage. For illustration purposes, FIG. 17 is a graph illustrating avariation of a normalized parameter of different distances between twopoint sources in the far field along with a frequency of sound accordingto some embodiments of the present disclosure. The abscissa mayrepresent the frequency (f) of the sound, the unit may be Hertz (Hz).The ordinate may use a normalization parameter a for evaluating thevolume of the leaked sound, and the unit may be decibel (dB). As shownin FIG. 17, taking the normalization parameter a of a single pointsource as a reference, as the distance between the two point sourcesincreases from d to 10 d, the normalization parameter a may graduallyincrease, indicating that the sound leakage may gradually increase. Moredescriptions regarding the normalization parameter a may be found inequation (4) and related descriptions.

In some embodiments, adding a baffle structure to the acoustic outputapparatus may be beneficial to improve the output effect of the acousticoutput apparatus, that is, to increase the sound intensity at thenear-field listening position, while reduce the volume of the far-fieldsound leakage. For illustration, FIG. 18 is a diagram illustrating anexemplary baffle provided between two point sources according to someembodiments of the present disclosure. As shown in FIG. 18, when abaffle is provided between the point source a1 and the point source a2,in the near field, the sound wave of the point source a2 may need tobypass the baffle to interfere with the sound wave of the point sourcea1 at the listening position, which may be equivalent to increasing thelength of the acoustic route from the point source a2 to the listeningposition. Therefore, assuming that the point source a1 and the pointsource a2 have a same amplitude, compared to the case without a baffle,the difference in the amplitude of the sound waves of the point sourcea1 and the point source a2 at the listening position may increase, sothat the degree of cancellation of the two sounds at the listeningposition may decrease, causing the sound volume at the listeningposition to increase. In the far field, because the sound wavesgenerated by the point source a1 and the point source a2 do not need tobypass the baffle in a large space, the sound waves may interfere(similar to the case without a baffle). Compared to the case without abaffle, the sound leakage in the far field may not increasesignificantly. Therefore, a baffle structure being provided between thepoint source a1 and the point source a2 may increase the sound volume atthe near-field listening position significantly while the volume of thefar-field leakage does not increase significantly.

In the present disclosure, when the two point sources are located onboth sides of the auricle, the auricle may serve as a baffle, so theauricle may also be referred to as a baffle for convenience. As anexample, due to the existence of the auricle, the result may beequivalent to that the near-field sound may be generated by two pointsources with a distance of D1 (also known as mode 1). The far-fieldsound may be generated by two point sources with a distance of D2 (alsoknown as mode 2), and D1>D2. FIG. 19 is a graph illustrating a variationof the volume of a sound heard by a user as a function of the frequencyof sound when the auricle is located between two point sources accordingto some embodiments of the present disclosure. As shown in FIG. 19, whenthe frequency is low (for example, when the frequency is less than 1000Hz), the volume at the near-field sound (that is, the sound heard by theuser by the user's ear) may basically be the same as that of thenear-field sound in mode 1, be greater than the volume of the near-fieldsound in mode 2, and be close to the volume of the near-field sound of asingle point source. As the frequency increases (for example, when thefrequency is between 2000 Hz and 7000 Hz), the volume of the near-fieldsound in mode 1 and the two point sources being distributed on bothsides of the auricle may be greater than that of the one point source.It shows that when the user's auricle is located between the two pointsources, the volume of the near-field sound transmitted from the soundsource to the user's ear may be effectively enhanced. FIG. 20 is a graphillustrating a variation of the volume of a leaked sound as a functionof the frequency of sound when the auricle is located between two pointsources according to some embodiments of the present disclosure. Asshown in FIG. 20, as the frequency increases, the volume of thefar-field leakage may increase. When the two point sources aredistributed on both sides of the auricle, the volume of the far-fieldleakage generated by the two point sources may be basically the same asthe volume of the far-field leakage in mode 2, and both of which may beless than the volume of the far-field leakage in mode 1 and the volumeof the far-field leakage of a single point source. It shows that whenthe user's auricle is located between the two point sources, the soundtransmitted from the sound source to the far field may be effectivelyreduced, that is, the sound leakage from the sound source to thesurrounding environment may be effectively reduced. FIG. 21 is a graphillustrating a variation of a normalized parameter as a function of thefrequency of sound when two point sources of an acoustic outputapparatus is distributed on both sides of the auricle according to someembodiments of the present disclosure. As shown in FIG. 21, when thefrequency is less than 10000 Hz, the normalized parameter of the twopoint sources being distributed on both sides of the auricle may be lessthan the normalized parameter in the case of mode 1 (no baffle structurebetween the two point sources, and the distance is D1), mode 2 (nobaffle structure between the two point sources, and the distance is D2),and the single point source, which may show that when the two pointsources are located on both sides of the auricle, the acoustic outputapparatus may have a better capability to reduce the sound leakage.

In order to further explain the effect of the acoustic output apparatuswith or without a baffle between the two point sources or two soundguiding holes, the volume of the near-field sound at the listeningposition and/or volume of the far-field leakage under differentconditions may specifically be described below.

FIG. 22 is a graph illustrating a variation of the volume of a soundheard by the user and volume of a leaked sound as a function of thefrequency of sound with and without a baffle between two point sourcesaccording to some embodiments of the present disclosure. As shown inFIG. 22, after adding a baffle between the two point sources (i.e., twosound guiding holes) of the acoustic output apparatus, in the nearfield, it may be equivalent to increasing the distance between the twopoint sources, and the sound volume at the near-field listening positionmay be equivalent to being generated by a set of two point sources witha large distance. The volume of the near-field sound may besignificantly increased compared to the case without a baffle. In thefar field, because the interference of the sound waves generated by thetwo point sources may be rarely affected by the baffle, the soundleakage may be equivalent to being generated by two point sources with asmall distance, therefore the sound leakage may not change significantlywith or without the baffle. It may be seen that by setting a bafflebetween two sound guiding holes (i.e., two point sources), the abilityof the sound output apparatus to reduce the sound leakage may beeffectively improved, and the volume of the near-field sound of theacoustic output apparatus may be increased significantly. Therefore, therequirements for sound production components of the acoustic outputapparatus may be reduced. At the same time, the simple circuit structuremay reduce the electrical loss of the acoustic output apparatus, so thatthe working time of the acoustic output apparatus may be greatlyprolonged under a certain amount of electricity.

FIG. 23 is a graph illustrating a variation of the volume of a soundheard by the user and the volume of a leaked sound as a function of thedistance between two point sources when the frequency of the two pointsources is 300 Hz according to some embodiments of the presentdisclosure. FIG. 24 is a graph illustrating a variation of the volume ofa sound heard by the user and the volume of a leaked sound as a functionof the distance between two point sources when the frequency of the twopoint sources is 1000 Hz according to some embodiments of the presentdisclosure. As shown in FIGS. 23 and 24, in the near field, when thefrequency is 300 Hz or 1000 Hz, as the increase of the distance d of thetwo point sources, the volume of the sound heard by the user with abaffle between the two point sources may be greater than that without abaffle between the two point sources, which shows that at thisfrequency, the baffle structure between the two point sources mayeffectively increase the volume of the sound heard by the user in thenear field. In the far field, the volume of the leaked sound with abaffle between the two point sources may be equivalent to that without abaffle between the two point sources, which shows that at thisfrequency, with or without a baffle structure arranged between the twopoint sources has little effect on the far-field sound leakage.

FIG. 25 is a graph illustrating a variation of the volume of a soundheard by the user and the volume of a leaked sound as a function of thedistance when the frequency of the two point sources is 5000 Hzaccording to some embodiments of the present disclosure. As shown inFIG. 25, in the near field, when the frequency is 5000 Hz, as thedistance d of the two point sources increases, the volume of the soundheard by the user when there is a baffle between the two point sourcesmay be greater than that when there is no baffle. In the far-field, thevolume of the leaked sound of the two point sources with and withoutbaffle may be fluctuant as a function of the distance d. Overall,whether the baffle structure is arranged between the two point sourceshas little effect on the far-field leakage.

FIGS. 26-28 are graphs illustrating a variation of the volume of a soundheard by the user as a function of the frequency of sound when thedistance d of two point sources is 1 cm, 2 cm, 3 cm, respectively,according to some embodiments of the present disclosure. FIG. 29 is agraph illustrating a variation of a normalized parameter of a far fieldas a function of the frequency of sound when the distance d of two pointsources is 1 cm according to some embodiments of the present disclosure.FIG. 30 is a graph illustrating a variation of a normalized parameter ofa far field as a function of the frequency of sound when the distance dof two point sources is 2 cm according to some embodiments of thepresent disclosure. FIG. 31 is a graph illustrating a variation of anormalized parameter of a far field as a function of the frequency ofsound when the distance d of two point sources is 4 cm according to someembodiments of the present disclosure. As shown in FIGS. 26 through 28,for the different distances d of the sound guiding holes (for example, 1cm, 2 cm, 4 cm), at a certain frequency, in the near-field listeningposition (for example, the user's ear), the sound volume of two soundguiding holes located on both sides of the auricle (i.e., the “baffleeffect” situation shown in the figure) may be greater than the soundvolume of two sound guiding holes located on a same side of the auricle(i.e., the case of “without baffle” as shown in the figures). Thecertain frequency may be below 10000 Hz, below 5000 Hz, or below 1000Hz.

As shown in FIGS. 29 to 31, for the different distances d of the soundguiding holes (for example, 1 cm, 2 cm, and 4 cm), at a certainfrequency, in the far-field position (for example, the environmentposition away from the user's ear), the volume of the leaked soundgenerated when the two sound guiding holes are provided on both sides ofthe auricle may be smaller than that generated when the two soundguiding holes are not provided on both sides of the auricle. It shouldbe noted that as the distance between two sound guiding holes or twopoint sources increases, the interference cancellation of sound at thefar-field position may weaken, leading to a gradual increase in thefar-field leakage and a weaker ability to reduce sound leakage.Therefore, the distance d between two sound guiding holes or the twopoint sources may not be too large. In some embodiments, in order tokeep the output sound as loud as possible in the near field, andsuppress the sound leakage in the far field, the distance d between thetwo sound guiding holes may be set to be no more than, for example, 20cm, 12 cm, 10 cm, 6 cm, or the like. In some embodiments, consideringthe size of the acoustic output apparatus and the structuralrequirements of the sound guiding holes, the distance d between the twosound guiding holes may be set to be in a range of, for example, 1 cm to12 cm, 1 cm to 10 cm, 1 cm to 8 cm, 1 cm to 6 cm, 1 cm to 3 cm, or thelike.

It should be noted that the above description is merely for theconvenience of description, and not intended to limit the scope of thepresent disclosure. It may be understood that, for those skilled in theart, after understanding the principle of the present disclosure,various modifications and changes in the forms and details of theacoustic output apparatus may be made without departing from thisprinciple. For example, in some embodiments, a plurality of soundguiding holes may be set on both sides of the baffle. The number of thesound guiding holes on both sides of the baffle may be the same ordifferent. For example, the number of sound guiding holes on one side ofthe baffle may be two, and the number of sound guiding holes on theother side may be two or three. These modifications and changes maystill be within the protection scope of the present disclosure.

In some embodiments, on the premise of maintaining the distance betweenthe two point sources, a relative position of the listening position tothe two point sources may have a certain effect on the volume of thenear-field sound and the far-field leakage reduction. In order toimprove the acoustic output effect of the acoustic output apparatus, insome embodiments, the acoustic output apparatus may be provided with atleast two sound guiding holes. The at least two sound guiding holes mayinclude two sound guiding holes located on the front and back sides ofthe user's auricle, respectively. In some embodiments, considering thatthe sound propagated from the sound guiding hole located on the rearside of the user's auricle needs to bypass over the auricle to reach theuser's ear canal, the acoustic route between the sound guiding holelocated on the front side of the auricle and the user's ear canal (i.e.,the acoustic distance from the sound guiding hole to the user's earcanal entrance) is shorter than the acoustic route between the soundguiding hole located on the rear side of the auricle and the user's ear.In order to further explain the effect of the listening position on theacoustic output effect, four representative listening positions(listening position 1, listening position 2, listening position 3,listening position 4) may be selected as shown in FIG. 32. The listeningposition 1, the listening position 2, and the listening position 3 mayhave equal distance from the point source a1, which may be r1. Thedistance between the listening position 4 and the point source a1 may ber2, and r2<r1. The point source a1 and the point source a2 may generatesounds with opposite phases, respectively.

FIG. 33 is a graph illustrating the volume of a sound heard by a user oftwo point sources without baffle at different listening positions as afunction of the frequency of sound according to some embodiments of thepresent disclosure. FIG. 34 is a graph illustrating a normalizedparameter of different listening positions as a function of thefrequency of sound. The normalized parameter may be obtained withreference to Equation (4). As shown in FIGS. 33 and 34, for thelistening position 1, since the difference between the acoustic routesfrom the point source a1 and the point source a2 to the listeningposition 1 is small, the difference in amplitude of the sounds producedby the two point sources at the listening position 1 may be small.Therefore, an interference of the sounds of the two point sources at thelistening position 1 may cause the volume of the sound heard by the userto be smaller than that of other listening positions. For the listeningposition 2, compared with the listening position 1, the distance betweenthe listening position 2 and the point source a1 may remain unchanged,that is, the acoustic route from the point source a1 to the listeningposition 2 may not change. However, the distance between the listeningposition 2 and the point source a2 may be longer, and the length of theacoustic route between the point source a2 and the listening position 2may increase. The amplitude difference between the sound generated bythe point source a1 and the sound generated by the point source a2 atthe listening position 2 may increase. Therefore, the volume of thesound transmitted from the two point sources after interference at thelistening position 2 may be greater than that at the listening position1. Among all positions on an arc with a radius of r1, a differencebetween the acoustic route from the point source a1 to the listeningposition 3 and the acoustic route from the point source a2 to thelistening position 3 may be the longest. Therefore, compared with thelistening position 1 and the listening position 2, the listeningposition 3 may have the highest volume of the sound heard by the user.For the listening position 4, the distance between the listeningposition 4 and the point source a1 may be short. The sound amplitude ofthe point source a1 at the listening position 4 may be large. Therefore,the volume of the sound heard by the user at the listening position 4may be large. In summary, the volume of the sound heard by the user atthe near-field listening position may change as the listening positionand the relative position of the two point sources change. When thelistening position is on the line between the two point sources and onthe same side of the two point sources (for example, listening position3), the acoustic route difference between the two point sources at thelistening position may be the largest (the acoustic route difference maybe the distance d between the two point sources). In this case (i.e.,when the auricle is not used as a baffle), the volume of the sound heardby the user at this listening position may be greater than that at otherlocations. According to Equation (4), when the far-field leakage isconstant, the normalization parameter corresponding to this listeningposition may be the smallest, and the leakage reduction capability maybe the strongest. At the same time, reducing the distance r1 between thelistening position (for example, listening position 4) and the pointsource a1 may further increase the volume at the listening position, atthe same time reduce the sound leakage, and improve the capability toreduce leakage.

FIG. 35 is a graph illustrating the volume of the sound heard by theuser of two point sources with baffle (as shown in FIG. 32) at differentlistening positions in the near field as a function of frequencyaccording to some embodiments of the present disclosure. FIG. 36 is agraph of the normalization parameters of different listening positionsobtained with reference to Equation (4) based on FIG. 35, as a functionof frequency. As shown in FIGS. 35 and 36, compared to the case withouta baffle, the volume of the sound heard by the user generated by the twopoint sources at listening position 1 may increase significantly whenthere is a baffle. The volume of the sound heard by the user at thelistening position 1 may exceed that at the listening position 2 and thelistening position 3. The reason may be that the acoustic route from thepoint source a2 to the listening position 1 may increase after a baffleis set between the two point sources. As a result, the acoustic routedifference between the two point sources at the listening position 1 mayincrease significantly. The amplitude difference between the soundsgenerated by the two point sources at the listening position 1 mayincrease, making it difficult to produce sound interferencecancellation, thereby increasing the volume of the sound heard by theuser generated at the listening position 1 significantly. At thelistening position 4, since the distance between the listening positionand the point source a1 is further reduced, the sound amplitude of thepoint source a1 at this position may be larger. The volume of the soundheard by the user at the listening position 4 may still be the largestamong the four listening positions. For listening position 2 andlistening position 3, since the effect of the baffle on the acousticroute from the point source a2 to the two listening positions is notvery obvious, the volume increase effect at the listening position 2 andthe listening position 3 may be less than that at the listening position1 and the listening position 4 which are closer to the baffle.

The volume of the leaked sound in the far field may not change withlistening positions, and the volume of the sound heard by the user atthe listening position in the near field may change with listeningpositions. In this case, according to Equation (4), the normalizationparameter of the acoustic output apparatus may vary in differentlistening positions. Specifically, a listening position with a largevolume of sound heard by the user (e.g., listening position 1 andlistening position 4) may have a small normalization parameter andstrong capability to reduce sound leakage. A listening position with alow volume of sound heard by the user (e.g., listening position 2 andlistening position 3) may have a large normalization parameter and weakcapability to reduce leakage.

Therefore, according to the actual application scenario of the acousticoutput apparatus, the user's auricle may serve as a baffle. In thiscase, the two sound guiding holes on the acoustic output apparatus maybe arranged on the front side and the back side of the auricle,respectively, and the ear canal may be located between the two soundguiding holes as a listening position. In some embodiments, by designingthe positions of the two sound guiding holes on the acoustic outputapparatus, the distance between the sound guiding hole on the front sideof the auricle and the ear canal may be smaller than the distancebetween the sound guiding hole on the back side of the auricle and theear canal. In this case, the acoustic output apparatus may produce alarge sound amplitude at the ear canal since the sound guiding hole onthe front side of the auricle is close to the ear canal. The soundamplitude formed by the sound guiding hole on the back of the auriclemay be smaller at the ear canal, which may avoid the interferencecancellation of the sound at the two sound guiding holes at the earcanal, thereby ensuring that the volume of the sound heard by the userat the ear canal is large. In some embodiments, the acoustic outputapparatus may include one or more contact points (e.g., “an inflectionpoint” on a supporting structure to match the shape of the ear) that cancontact with the auricle when it is worn. The contact point(s) may belocated on a line connecting the two sound guiding holes or on one sideof the line connecting the two sound guiding holes. And a ratio of thedistance between the front sound guiding hole and the contact point(s)to the distance between the rear sound guiding hole and the contactpoint(s) may be 0.05-20. In some embodiments, the ratio may be 0.1-10.In some embodiments, the ratio may be 0.2-5. In some embodiments, theratio may be 0.4-2.5.

FIG. 37 is a schematic diagram illustrating two point sources and abaffle (e.g., an auricle) according to some embodiments of the presentdisclosure. In some embodiments, a position of the baffle between thetwo sound guiding holes may have a certain influence on the acousticoutput effect. Merely by way of example, as shown in FIG. 37, a bafflemay be provided between a point source a1 and a point source a2, alistening position may be located on the line connecting the pointsource a1 and the point source a2. In addition, the listening positionmay be located between the point source a1 and the baffle. A distancebetween the point source a1 and the baffle may be L. A distance betweenthe point source a1 and the point source a2 may be d. A distance betweenthe point source a1 and the sound heard by the user may be L1. Adistance between the listening position and the baffle may be L2. Whenthe distance L1 is constant, a movement of the baffle may causedifferent ratios of L to d, thereby obtaining different volumes of thesound heard by the user at the listening position and/or the volumes ofthe far-field leakage.

FIG. 38 is a graph illustrating a variation of the volume of anear-field sound as a function of the frequency of sound when a baffleis at different positions according to some embodiments of the presentdisclosure. FIG. 39 is a graph illustrating a variation of the volume ofa far-field leakage as a function of the frequency of sound when abaffle is at different positions according to some embodiments of thepresent disclosure. FIG. 40 is a graph illustrating a variation of anormalization parameter as a function of the frequency of sound when abaffle is at different positions according to some embodiments of thepresent disclosure. According to FIGS. 38-40, the volume of thefar-field leakage may vary little with the change of the position of thebaffle between the two point sources. In a situation that the distance dbetween the point source a1 and the point source a2 remains constant,when L decreases, the volume at the listening position may increase, thenormalization parameter may decrease, and the capability to reduce soundleakage may be enhanced. In the same situation, when L increases, thevolume at the listening position may increase, the normalizationparameter may increase, and the capability to reduce sound leakage maybe weakened. A reason for the above result may be that when L is small,the listening position may be close to the baffle, an acoustic route ofthe sound wave from the point source a2 to the listening position may beincreased due to the baffle. In this case, an acoustic route differencebetween the point source a1 and the point source a2 to the listeningposition may be increased and the interference cancellation of the soundmay be reduced. As a result, the volume at the listening position may beincreased after the baffle is added. When L is large, the listeningposition may be far away from the baffle. The baffle may have a smalleffect on the acoustic route difference between the point source a1 andthe point source a2 to the listening position. As a result, a volumechange at the listening position may be small after the baffle is added.

As described above, by designing positions of the sound guiding holes onthe acoustic output apparatus, an auricle of a human body may serve as abaffle to separate different sound guiding holes when the user wears theacoustic output apparatus. In this case, a structure of the acousticoutput apparatus may be simplified, and the output effect of theacoustic output apparatus may be further improved. In some embodiments,the positions of the two sound guiding holes may be properly designed sothat a ratio of a distance between the sound guiding hole on the frontside of the auricle and the auricle (or a contact point on the acousticoutput apparatus for contact with the auricle) to a distance between thetwo sound guiding holes may be less than or equal to 0.5 when the userwears the acoustic output apparatus. In some embodiments, the ratio maybe less than or equal to 0.3. In some embodiments, the ratio may be lessthan or equal to 0.1. In some embodiments, the ratio of the distancebetween the sound guiding hole on the front side of the auricle and theauricle (or a contact point on the acoustic output apparatus for contactwith the auricle) to the distance between the two sound guiding holesmay be larger than or equal to 0.05. In some embodiments, a second ratioof the distance between the two sound guiding holes to a height of theauricle may be larger than or equal to 0.2. In some embodiments, thesecond ratio may be less than or equal to 4. In some embodiments, theheight of the auricle may refer to a length of the auricle in adirection perpendicular to a sagittal plane.

It should be noted that an acoustic route from an acoustic driver to asound guiding hole in the acoustic output apparatus may have a certaineffect on the volumes of the near-field sound and far-field soundleakage. The acoustic route may be changed by adjusting a cavity lengthbetween a vibration diaphragm in the acoustic output apparatus and thesound guiding hole. In some embodiments, the acoustic driver may includea vibration diaphragm. The front and rear sides of the vibrationdiaphragm may be coupled to two sound guiding holes through a frontchamber and a rear chamber, respectively. The acoustic routes from thevibration diaphragm to the two sound guiding holes may be different. Insome embodiments, a ratio of the lengths of the acoustic routes betweenthe vibration diaphragm and the two sound guiding holes may be, forexample, 0.5-2, 0.6-1.5, or 0.8-1.2.

In some embodiments, on the premise of keeping the phases of the soundsgenerated at the two sound guiding holes opposite, the amplitudes of thesounds generated at the two sound guiding holes may be changed toimprove the output effect of the acoustic output apparatus.Specifically, impedances of acoustic routes connecting the acousticdriver and the two sound guiding holes may be adjusted so as to adjustthe sound amplitude at each of the two sound guiding holes. In someembodiments, the impedance may refer to a resistance that a medium needsto overcome during displacement when acoustic waves are transmitted. Theacoustic routes may or may not be filled with a damping material (e.g.,a tuning net, a tuning cotton, etc.) so as to adjust the soundamplitude. For example, a resonance cavity, a sound hole, a sound slit,a tuning net, and/or a tuning cotton may be disposed in an acousticroute so as to adjust the acoustic resistance, thereby changing theimpedances of the acoustic route. As another example, an aperture ofeach of the two sound guiding holes may be adjusted to change theacoustic resistance of the acoustic routes corresponding to the twosound guiding holes. In some embodiments, a ratio of the acousticimpedance of the acoustic route between the acoustic driver (thevibration diaphragm) and one of the two sound guiding holes to theacoustic route between the acoustic driver and the other sound guidinghole may be 0.5-2 or 0.8-1.2.

It should be noted that the above descriptions are merely forillustration purposes, and not intended to limit the present disclosure.It should be understood that, for those skilled in the art, afterunderstanding the principle of the present disclosure, variousmodifications and changes may be made in the forms and details of theacoustic output apparatus without departing from this principle. Forexample, the listening position may not be on the line connecting thetwo point sources, but may also be above, below, or in an extensiondirection of the line connecting the two point sources. As anotherexample, a measurement method of the distance from a point sound sourceto the auricle, and a measurement method of the height of the auriclemay also be adjusted according to different scenarios. These similarchanges may be all within the protection scope of the presentdisclosure.

FIG. 41 is a schematic diagram illustrating another exemplary acousticoutput apparatus according to some embodiments of the presentdisclosure.

For human ears, the frequency band of sound that can be heard may beconcentrated in a mid-low-frequency band. An optimization goal in themid-low-frequency band may be to increase a volume of the sound heard bythe user. If the listening position is fixed, parameters of the twopoint sources may be adjusted such that the volume of the sound heard bythe user may increase significantly while a volume of leaked sound maybe substantially unchanged (an increase in the volume of the sound heardby the user may be greater than an increase in the volume of the soundleakage). In a high-frequency band, a sound leakage reduction effect ofthe two point sources may be weaker. In the high-frequency band, anoptimization goal may be reducing a sound leakage. The sound leakage maybe further reduced by adjusting the parameters of the two point sourcesof different frequencies. In some embodiments, the acoustic outputapparatus 1400 may also include an acoustic driver 1430. The acousticdriver 1430 may output sounds from two of second sound guiding holes.Details regarding the acoustic driver 1430, the second sound guidingholes, and a structure therebetween may be described with reference tothe acoustic driver 1420 and the first sound guiding holes. In someembodiments, the acoustic driver 1430 and the acoustic driver 1420 mayoutput sounds of different frequencies. In some embodiments, theacoustic output apparatus may further include a controller configured tocause the acoustic driver 1420 to output sound in the first frequencyrange, and cause the acoustic driver 1430 to output sound in the secondfrequency range. The second frequency range may include frequencieshigher than the first frequency range. For example, the first frequencyrange may be 100 Hz-1000 Hz, and the second frequency range may be 1000Hz-10000 Hz.

In some embodiments, the acoustic driver 1420 may be a low-frequencyspeaker, and the acoustic driver 1430 may be a mid-high-frequencyspeaker. Due to different frequency response characteristics of thelow-frequency speaker and the mid-high-frequency speaker, frequencybands of the output sound may also be different. High-frequency bandsand low-frequency bands may be divided by using the low-frequencyspeakers and the mid-high-frequency speakers, and accordingly, twolow-frequency point sources and two mid-high-frequency point sources maybe constructed to perform near-field sound output and a far-fieldleakage reduction. For example, the acoustic driver 1420 may provide twopoint sources for outputting low-frequency sound through the soundguiding hole 1411 and the sound guiding hole 1412, which may be mainlyused for outputting sound in low-frequency band. The two low-frequencypoint sources may be distributed on both sides of an auricle to increasea volume near the near-field ear. The acoustic driver 1430 may providetwo point sources for outputting mid-high-frequency sound through twosecond sound guiding holes. A mid-high-frequency sound leakage may bereduced by adjusting a distance between the two second sound guidingholes. The two mid-high-frequency point sources may be distributed onboth sides of the auricle or on the same side of the auricle.Alternatively, the acoustic driver 1420 may provide two point sourcesfor outputting full-frequency sound through the sound guiding hole 1411and the sound guiding hole 1412 so as to further increase the volume ofthe near-field sound.

Further, the distance d2 between the two second sound guiding holes maybe less than the distance d1 between the sound guiding hole 1411 and thesound guiding hole 1412, that is, d1 may be larger than d2. Forillustration purpose, as shown in FIG. 13, it may be possible to obtaina stronger sound leakage reduction capability than a single point sourceand one set of two point sources by setting two sets of two pointsources including one set of two low-frequency point sources and one setof two high-frequency point sources with different distances.

It should be noted that the positions of the sound guiding holes of theacoustic output apparatus may be not limited to the case that the twosound guiding holes 1411 and 1412 corresponding to the acoustic driver1420 shown in FIG. 41 are distributed on both sides of the auricle, andthe case that the two sound guiding holes corresponding to the acousticdriver 1430 are distributed on the front side of the auricle. Forexample, in some embodiments, two second sound guiding holescorresponding to the acoustic driver 1430 may be distributed on the sameside of the auricle (e.g., a rear side, an upper side, or a lower sideof the auricle). As another example, in some embodiments, the two secondsound guiding holes corresponding to the acoustic driver 1430 may bedistributed on both sides of the auricle. In some embodiments, when thesound guiding holes 1411 and the sound guiding hole 1412 (and/or the twosecond sound guiding holes) are located on the same side of the auricle,a baffle may be disposed between the sound guiding holes 1411 and thesound guiding hole 1412 (and/or the two second sound guiding holes) soas to further increase the volume of the near-field sound and reduce thefar-field sound leakage. For a further example, in some embodiments, thetwo sound guiding holes corresponding to the acoustic driver 1420 mayalso be located on the same side of the auricle (e.g., a front side, arear side, an upper side, or a lower side of the auricle).

In practical applications, the acoustic output apparatus may includedifferent application forms such as bracelets, glasses, helmets,watches, clothings, or backpacks, smart headsets, etc. In someembodiments, an augmented reality technology and/or a virtual realitytechnology may be applied in the acoustic output apparatus so as toenhance a user's audio experience. For illustration purposes, a pair ofglasses with a sound output function may be provided as an example.Exemplary glasses may be or include augmented reality (AR) glasses,virtual reality (VR) glasses, etc.

FIG. 42 is a schematic diagram illustrating an exemplary acoustic outputapparatus customized for augmented reality according to some embodimentsof the present disclosure. Merely for illustration purposes, theacoustic output apparatus 4200 may be or include an AR glasses. The ARglasses may include a frame and lenses. The AR glasses may be providedwith a plurality of components which may implement different functions.Details regarding structures and components of the AR glasses may bedescribed with reference to the glasses 100 illustrated in FIG. 1. Insome embodiments, the acoustic output apparatus 4200 may include asensor module 4210 and a processing engine 4220. In some embodiments,the power source assembly may also provide electrical power to thesensor module 4210 and/or the processing engine 4220.

The sensor module 4210 may include a plurality of sensors of varioustypes. The plurality of sensors may detect status information of a user(e.g., a wearer) of the acoustic output apparatus. The statusinformation may include, for example, a location of the user, a gestureof the user, a direction that the user faces, an acceleration of theuser, a speech of the user, etc. A controller (e.g., the processingengine 4220) may process the detected status information, and cause oneor more components of the acoustic output apparatus 4200 to implementvarious functions or methods described in the present disclosure. Forexample, the controller may cause at least one acoustic driver to outputsound based on the detected status information. The sound output may beoriginated from audio data from an audio source (e.g., a terminal deviceof the user, a virtual audio marker associated with a geographiclocation, etc.). The plurality of sensors may include a locating sensor4211, an orientation sensor 4212, an inertial sensor 4213, an audiosensor 4214, and a wireless transceiver 4215. Merely for illustration,only one sensor of each type is illustrated in FIG. 42. Multiple sensorsof each type may also be contemplated. For example, two or more audiosensors may be used to detect sounds from different directions.

The locating sensor 4211 may determine a geographic location of theacoustic output apparatus 4200. The locating sensor 4211 may determinethe location of the acoustic output apparatus 4200 based on one or morelocation-based detection systems such as a global positioning system(GPS), a Wi-Fi location system, an infra-red (IR) location system, abluetooth beacon system, etc. The locating sensor 4211 may detectchanges in the geographic location of the acoustic output apparatus 4200and/or a user (e.g., the user may wear the acoustic output apparatus4200, or may be separated from the acoustic output apparatus 4200) andgenerate sensor data indicating the changes in the geographic locationof the acoustic output apparatus 4200 and/or the user.

The orientation sensor 4212 may track an orientation of the user and/orthe acoustic output apparatus 4200. The orientation sensor 4212 mayinclude a head-tracking device and/or a torso-tracking device fordetecting a direction in which the user is facing, as well as themovement of the user and/or the acoustic output apparatus 4200.Exemplary head-tracking devices or torso-tracking devices may include anoptical-based tracking device (e.g., an optical camera), anaccelerometer, a magnetometer, a gyroscope, a radar, etc. In someembodiments, the orientation sensor 4212 may detect a change in theuser's orientation, such as a turning of the torso or an about-facemovement, and generate sensor data indicating the change in theorientation of the body of the user.

The inertial sensor 4213 may sense gestures of the user or a body part(e.g., head, torso, limbs) of the user. The inertial sensor 4213 mayinclude an accelerometer, a gyroscope, a magnetometer, or the like, orany combination thereof. In some embodiments, the accelerometer, thegyroscope, and/or the magnetometer may be independent components. Insome embodiments, the accelerometer, the gyroscope, and/or themagnetometer may be integrated or collectively housed in a single sensorcomponent. In some embodiments, the inertial sensor 4213 may detect anacceleration, a deceleration, a tilt level, a relative position in thethree-dimensional (3D) space, etc. of the user or a body part (e.g., anarm, a finger, a leg, etc.) of the user, and generate sensor dataregarding the gestures of the user accordingly.

The audio sensor 4214 may detect sound from the user, a smart device4240, and/or ambient environment. In some embodiments, the audio sensor4214 may include one or more microphones, or a microphone array. The oneor more microphones or the microphone array may be housed within theacoustic output apparatus 4200 or in another device connected to theacoustic output apparatus 4200. In some embodiments, the one or moremicrophones or the microphone array may be generic microphones. In someembodiments, the one or more microphones or the microphone array may becustomized for VR and/or AR.

In some embodiments, the audio sensor 4214 may be positioned so as toreceive audio signals proximate to the acoustic output apparatus 4200,e.g., speech/voice input by the user to enable a voice controlfunctionality. For example, the audio sensor 4214 may detect sounds ofthe user wearing the acoustic output apparatus 4200 and/or other usersproximate to or interacting with the user. The audio sensor 4214 mayfurther generate sensor data based on the received audio signals.

The wireless transceiver 4215 may communicate with other transceiverdevices in distinct locations. The wireless transceiver 4215 may includea transmitter and a receiver. Exemplary wireless transceivers mayinclude, for example, a Local Area Network (LAN) transceiver, a WideArea Network (WAN) transceiver, a ZigBee transceiver, a Near FieldCommunication (NFC) transceiver, a bluetooth (BT) transceiver, abluetooth Low Energy (BTLE) transceiver, or the like, or any combinationthereof. In some embodiments, the wireless transceiver 4215 may beconfigured to detect an audio message (e.g., an audio cache or pin)proximate to the acoustic output apparatus 4200, e.g., in a localnetwork at a geographic location or in a cloud storage system connectedwith the geographic location. For example, another user, a businessestablishment, a government entity, a tour group, etc. may leave anaudio message at a particular geographic or virtual location, and thewireless transceiver 4215 may detect the audio message, and prompt theuser to initiate a playback of the audio message.

In some embodiments, the sensor module 4210 (e.g., the locating sensor4211, the orientation sensor 4212, and the inertial sensor 4213) maydetect that the user moves toward or looks in a direction of a point ofinterest (POI). The POI may be an entity corresponding to a geographicor virtual location. The entity may include a building (e.g., a school,a skyscraper, a bus station, a subway station, etc.), a landscape (e.g.,a park, a mountain, etc.), or the like. In some embodiments, the entitymay be an object specified by a user. For example, the entity may be afavorite coffee shop of the user. In some embodiments, the POI may beassociated with a virtual audio marker. One or more localized audiomessages may be attached to the audio marker. The one or more localizedaudio message may include, for example, a song, a pre-recorded message,an audio signature, an advertisement, a notification, or the like, orany combination thereof.

The processing engine 4220 may include a sensor data processing module4221 and a retrieve module 4222. The sensor data processing module 4221may process sensor data obtained from the sensor module 4210 (e.g., thelocating sensor 4211, the orientation sensor 4212, the inertial sensor4213, the audio sensor 4214, and/or the wireless transceiver 4215), andgenerate processed information and/or data. The information and/or datagenerated by the sensor data processing module 4221 may include asignal, a representation, an instruction, or the like, or anycombination thereof. For example, the sensor data processing module 4221may receive sensor data indicating the location of the acoustic outputapparatus 4200, and determine whether the user is proximate to a POI orwhether the user is facing towards a POI. In response to a determinationthat the user is proximate to the POI or the user is facing towards thePOI, the sensor data processing module 4221 may generate a signal and/oran instruction used for causing the retrieve module 4222 to obtain anaudio message (i.e., a localized audio message associated with the POI).The audio message may be further provided to the user via the acousticoutput apparatus 4200 for playback.

Optionally or additionally, during the playback of the audio message, anactive noise reduction (ANR) technique may be performed so as to reducenoise. As used herein, the ANR may refer to a method for reducingundesirable sound by generating additional sound specifically designedto cancel the noise in the audio message according to the reversed phasecancellation principle. The additional sound may have an reversed phase,a same amplitude, and a same frequency as the noise. Merely by way ofexample, the acoustic output apparatus 4200 may include an ANR module(not shown) configured to reduce the noise. The ANR module may receivesensor data generated by the audio sensor 4214, signals generated by theprocessing engine 4220 based on the sensor data, or the audio messagesreceived via the wireless transceiver 4215, etc. The received data,signals, audio messages, etc. may include sound from a plurality ofdirections, which may include desired sound received from a certaindirection and undesired sound (i.e., noise) received from otherdirections. The ANR module may analyze the noise, and perform an ANRoperation to suppress or eliminate the noise.

In some embodiments, the ANR module may provide a signal to a transducer(e.g., the transducer 843, the transducer 853, or any other transducers)disposed in the acoustic output apparatus to generate an anti-noiseacoustic signal. The anti-noise acoustic signal may reduce orsubstantially prevent the noises from being heard by the user. In someembodiments, the anti-noise acoustic signal may be generated accordingto the noise detected by the acoustic output apparatus (e.g., the audiosensor 4214). For example, the anti-noise acoustic signal may have asame amplitude, a same frequency, and a reverse phase as the detectednoise.

The processing engine 4220 may be coupled (e.g., via wireless and/orwired connections) to a memory 4230. The memory 4230 may be implementedby any storage device capable of storing data. In some embodiments, thememory 4230 may be located in a local server or a cloud-based server,etc. In some embodiments, the memory 4230 may include a plurality ofaudio files 4231 for playback by the acoustic output apparatus 4200and/or user data 4232 of one or more users. The audio files 4231 mayinclude audio messages (e.g., audio pins or caches created by the useror other users), audio information provided by automated agents, orother audio files available from network sources coupled with a networkinterface, such as a network-attached storage (NAS) device, a DLNAserver, etc. The audio files 4231 may be accessible by the acousticoutput apparatus 4200 over a local area network such as a wireless(e.g., Wi-Fi) or wired (e.g., Ethernet) network. For example, the audiofiles 4231 may include localized audio messages attached to virtualaudio markers associated with a POI, which may be accessed when a useris proximate to or facing towards a POI.

The user data 4232 may be user-specific, community-specific,device-specific, location-specific, etc. In some embodiments, the userdata 4232 may include audio information related to one or more users.Merely by ways of example, the user data 4232 may include user-definedplaylists of digital music files, audio messages stored by the user orother users, information about frequently played audio files associatedwith the user or other similar users (e.g., those with common audio filelistening histories, demographic traits, or Internet browsinghistories), “liked” or otherwise favored audio files associated with theuser or other users, a frequency at which the audio files 4231 areupdated by the user or other users, or the like, or any combinationthereof. In some embodiments, the the user data 4232 may further includebasic information of the one or more users. Exemplary basis informationmay include names, ages, careers, habits, preferences, etc.

The processing engine 4220 may also be coupled with a smart device 4240that has access to user data (e.g., the user data 4232) or biometricinformation about the user. The smart device 4240 may include one ormore personal computing devices (e.g., a desktop or laptop computer),wearable smart devices (e.g., a smart watch, a smart glasses), a smartphone, a remote control device, a smart beacon device (e.g., a smartbluetooth beacon system), a stationary speaker system, or the like, orany combination thereof. In some embodiments, the smart device 4240 mayinclude a conventional user interface for permitting interaction withthe user, one or more network interfaces for interacting with theprocessing engine 4220 and other components in the acoustic outputapparatus 4200. In some embodiments, the smart device 4240 may beutilized to connect the acoustic output apparatus 4200 to a Wi-Finetwork, creating a system account for the user, setting up music and/orlocation-based audio services, browsing content for playback, settingassignments of the acoustic output apparatus 4200 or other audioplayback devices, transporting control (e.g., play/pause, fastforward/rewind, etc.) of the acoustic output apparatus 4200, selectingone or more acoustic output apparatus for content playback (e.g., asingle room playback or a synchronized multi-room playback), etc. Insome embodiments, the smart device 4240 may further include sensors formeasuring biometric information about the user. Exemplary biometricinformation may include travel, sleep, or exercise patterns, bodytemperature, heart rates, paces of gait (e.g., via accelerometers), orthe like, or any combination thereof.

The retrieve module 4222 may be configured to retrieve data from thememory 4230 and/or the smart device 4240 based on the information and/ordata generated by the sensor data processing module 4221, and determineaudio message for playback. For example, the sensor data processingmodule 4221 may analyze one or more voice commands from the user(obtained from the audio sensor 4214), and determine an instructionbased on the one or more voice commands. The retrieve module 4222 mayobtain and/or modify a localized audio message based on the instruction.As another example, the sensor data processing module 4221 may generatesignals indicating that a user is proximate to a POI and/or the user isfacing towards the POI. Accordingly, the retrieve module 4222 may obtaina localized audio message associated with the POI based on the signals.As a further example, the sensor data processing module 4221 maygenerate a representation indicating a characteristic of a location as acombination of factors from the sensor data, the user data 4232 and/orinformation from the smart device 4240. The retrieve module 4222 mayobtain the audio message based on the representation.

FIG. 43 is a flowchart illustrating an exemplary process for replayingan audio message according to some embodiments of the presentdisclosure.

In 4310, a point of interest (POI) may be detected. In some embodiments,the POI may be detected by the sensor module 4210 of the acoustic outputapparatus 4200.

As used herein, the POI may be an entity corresponding to a geographicor virtual location. The entity may include a building (e.g., a school,a skyscraper, a bus station, a subway station, etc.), a landscape (e.g.,a park, a mountain, etc.), or the like, or any combination thereof. Insome embodiments, the entity may be an object specified by the user. Forexample, the entity may be a favorite coffee shop of the user. In someembodiments, the POI may be associated with a virtual audio marker. Oneor more localized audio messages may be attached to the audio marker.The one or more localized audio message may include, for example, asong, a pre-recorded message, an audio signature, an advertisement, anotification, or the like, or any combination thereof.

In some embodiments, the sensor module 4210 (e.g., the locating sensor4211, the orientation sensor 4212, and the inertial sensor 4213) maydetect that a user wearing the acoustic output apparatus 4200 movestoward to or looks in the direction of the POI. Specifically, the sensormodule 4210 (e.g., the locating sensor 4211) may detect changes in ageographic location of the user, and generate sensor data indicating thechanges in the geographic location of the user. The sensor module 4210(e.g., the orientation sensor 4212) may detect changes in an orientationof the user (e.g., the head of the user), and generate sensor dataindicating the changes in the orientation of the user. The sensor module4210 (e.g., the inertial sensor 4213) may also detect gestures (e.g.,via an acceleration, a deceleration, a tilt level, a relative positionin the three-dimensional (3D) space, etc. of the user or a body part(e.g., an arm, a finger, a leg, etc.)) of the user, and generate sensordata indicating the gestures of the user. The sensor data may betransmitted, for example, to the processing engine 4220 for furtherprocessing. For example, the processing engine 4220 (e.g., the sensordata processing module 4221) may process the sensor data, and determinewhether the user moves toward to or looks in the direction of the POI.

In some embodiments, other information may also be detected. Forexample, the sensor module 4210 (e.g., the audio sensor 4214) may detectsound from the user, a smart device (e.g., the smart device 4240),and/or ambient environment. Specifically, one or more microphones or amicrophone array may be housed within the acoustic output apparatus 4200or in another device connected to the acoustic output apparatus 4200.The sensor module 4210 may detect sound using the one or moremicrophones or the microphone array. In some embodiments, the sensormodule 4210 (e.g., the wireless transceiver 4215) may communicate withtransceiver devices in distinct locations, and detect an audio message(e.g., an audio cache or pin) when the acoustic output apparatus 4200 isproximate to the transceiver devices. In some embodiments, otherinformation may also be transmitted as part of the sensor data to theprocessing engine 4220 for processing.

In 4320, an audio message related to the POI may be determined. In someembodiments, the audio message related to the POI may be determined bythe processing engine 4220.

In some embodiments, the processing engine 4220 (e.g., the sensor dataprocessing module 4221) may generate information and/or data based atleast in part on the sensor data. The information and/or data include asignal, a representation, an instruction, or the like, or anycombination thereof. Merely by way of example, the sensor dataprocessing module 4221 may receive sensor data indicating a location ofa user, and determine whether the user is proximate to or facing towardsthe POI. In response to a determination that the user is proximate tothe POI or facing towards the POI, the sensor data processing module4221 may generate a signal and/or an instruction causing the retrievemodule 4222 to obtain an audio message (i.e., a localized audio messageattached to an audio marker associated with the POI). As anotherexample, the sensor data processing module 4221 may analyze sensor datarelated to a voice command detected from a user (e.g., by performing anatural language processing), and generate a signal and/or aninstruction related to the voice command. As a further example, thesensor data processing module 4221 may generate a representation byweighting the sensor data, user data (e.g., the user data 4232), andother available data (e.g., a demographic profile of a plurality ofusers with at least one common attribute with the user, a categoricalpopularity of an audio file, etc.). The representation may indicate ageneral characteristic of a location as a combination of factors fromthe sensor data, the user data and/or information from a smart device.

Further, the processing engine 4220 (e.g., the retrieve module 4222) maydetermine an audio message related to the POI based on the generatedinformation and/or the data. For example, the processing engine 4220 mayretrieve an audio message from the audio files 4231 in the memory 4230based on a signal and/or an instruction related to a voice command. Asanother example, the processing engine 4220 may retrieve an audiomessage based on a representation and relationships between therepresentation and the audio files 4231. The relationships may bepredetermined and stored in a storage device. As a further example, theprocessing engine 4220 may retrieve a localized audio message related toa POI when a user is proximate to or facing towards the POI. In someembodiments, the processing engine 4220 may determine two or more audiomessages related to the POI based on the information and/or the data.For example, when a user is proximate to or facing towards the POI, theprocessing engine 4220 may determine audio messages including “liked”music files, audio files accessed by other users at the POI, or thelike, or any combination thereof.

Taking an acoustic output apparatus customized for VR as an example, theacoustic output apparatus may determine an audio message related to aPOI based at least in part on sensor data obtained by sensors disposedin the acoustic output apparatus. For example, the POI may be ahistorical site associated with a virtual audio marker having one ormore localized audio messages. When the user wearing the acoustic outputapparatus is proximate to or facing towards the historical site, thelocalized audio messages may be recommended to the user via a virtualinterface. The one or more localized audio messages may include virtualenvironment data used to relive historical stories of the historicalsite. In the virtual environment data, sound data may be properlydesigned for simulating sound effects of different scenarios. Forexample, sound may be transmitted from different sound guiding holes tosimulate sound effects of different directions. As another example, thevolume and/or delay of sound may be adjusted to simulate sound effectsat different distances.

Taking an acoustic output apparatus customized for AR as anotherexample, the acoustic output apparatus may determine an audio messagerelated to a POI based at least in part on sensor data obtained bysensors disposed in the acoustic output apparatus. Additionally, theaudio message may be combined with real-world sound in ambientenvironment so as to enhance an audio experience of the user. Thereal-world sound in ambient environment may include sounds in alldirections of the ambient environment, or may be sounds in a certaindirection. Merely by way of example, FIG. 44 is a schematic diagramillustrating an exemplary acoustic output apparatus focusing on soundsin a certain direction according to some embodiments of the presentdisclosure. As illustrated in FIG. 44, when a user is proximate to a POIP, an acoustic output apparatus (e.g., the acoustic output apparatus4200) worn by the user may focus on sound received from a virtual audiocone. The vertex of the virtual audio cone may be the acoustic outputapparatus. The virtual audio cone may have any suitable size, which maybe determined by an angle of the virtual audio cone. For example, theacoustic output apparatus may focus on sound of a virtual audio conewith an angle of, for example, 20°, 40°, 60°, 80°, 120°, 180°, 270°,360°, etc. In some embodiments, to focus on sound within the range ofthe virtual audio cone, the acoustic output apparatus may improveaudibility of most or all sound in the virtual audio cone. For example,an ANR technique may be used by the acoustic output apparatus so as toreduce or substantially prevent sound in other directions (e.g., soundsoutside of the virtual audio cones) from being heard by the user.Additionally, the POI may be associated with virtual audio markers towhich localized audio messages may be attached. The localized audiomessages may be accessed when the user is proximate to or facing towardsthe POI. That is, the localized audio messages may be overlaid on thesound in the virtual audio cone so as to enhance an audio experience ofthe user. In some embodiments, a direction and/or a virtual audio coneof the sound focused by the acoustic output apparatus may be determinedaccording to actual needs. For example, the acoustic output apparatusmay focus on sound in a plurality of virtual audio cones in differentdirections simultaneously. As another example, the acoustic outputapparatus may focus on sound in a specified direction (e.g., the northdirection). As a further example, the acoustic output apparatus mayfocus on sound in a walking direction and/or a facing direction of theuser.

In 4330, the audio message may be replayed. In some embodiments, theaudio message may be replayed by the processing engine 4220.

In some embodiments, the processing engine 4220 may replay the audiomessage via the acoustic output apparatus 4200 directly. In someembodiments, the processing engine 4220 may prompt the user to initiatea playback of the audio message. For example, the processing engine 4220may output a prompt (e.g., a voice prompt via a sound guiding hole, avisual representation via a virtual user-interface) to the user. Theuser may respond to the prompt by interacting with the acoustic outputapparatus 4200. For example, the user may interact with the acousticoutput apparatus 4200 using, for example, gestures of his/her body(e.g., head, torso, limbs, eyeballs), voice command, etc.

Taking an acoustic output apparatus customized for AR as anotherexample, the user may interact with the acoustic output apparatus via avirtual user-interface (UI). FIG. 45 is a schematic diagram illustratingan exemplary UI of the acoustic output apparatus. As illustrated in FIG.45, the virtual UI may be present in a head position and/or a gazedirection of the user. In some embodiments, the acoustic outputapparatus may provide a plurality of audio samples, information, orchoices corresponding to spatially delineated zones (e.g., 4510, 4520,4530, 4540) in an array defined relative to a physical position of theacoustic output apparatus. Each audio sample or piece of informationprovided to the user may correspond to an audio message to be replayed.In some embodiments, the audio samples may include a selection of anaudio file or stream, such as a representative segment of the audiocontent (e.g., an introduction to an audio book, a highlight from asporting broadcast, a description of the audio file or stream, adescription of an audio pin, an indicator of the presence of an audiopin, an audio beacon, a source of an audio message). In someembodiments, the audio samples may include entire audio content (e.g.,an entire audio file). In some embodiments, the audio samples,information, or choices may be used as prompts for the user. The usermay respond to the prompts by interacting with the acoustic outputapparatus. For example, the user may click on a zone (e.g., 4520) toinitiate a playback of entire audio content corresponding to the audiosample presented in the zone. As another example, the user may shakehis/her head to switch between different zones.

Beneficial effects of the present disclosure may include but not limitedto: (1) wires or connections between different elements or componentsinside the acoustic output apparatus may be simplified; (2) mutualinfluence between wires or connections may be reduced and sound qualityof the acoustic output apparatus may be improved; (3) a pair ofhigh-frequency two point sources and a pair of low-frequency two pointsources may be provided to output sound in different frequency bands,thereby achieving better acoustic output effect; (4) two point sourceswith different distances may be provided, such that the acoustic outputapparatus may have a stronger capability to reduce sound leakage inhigher frequency bands, which may meet requirements for an open acousticoutput apparatus; (5) an acoustic route difference between two pointsources and a listening position may be increased by disposing a bafflestructure, which may improve a volume of sound heard by the user in thenear field and reduce a volume of leaked sound in the far field, therebyproviding a better acoustic output effect; (6) AR technology and/or VRtechnology may be combined with the acoustic output apparatus so as toenhance the user's audio experience. It should be noted that differentembodiments may have different beneficial effects. In variousembodiments, the acoustic output apparatus may have any one or acombination of the benefits exemplified above, and any other beneficialeffects that can be obtained.

1. An acoustic output apparatus, comprising: an earphone core includingat least one acoustic driver for outputting sound through one or moresound guiding holes set on the acoustic output apparatus, the at leastone acoustic driver comprising a low-frequency acoustic driver thatoutputs sound from at least two first sound guiding holes and ahigh-frequency acoustic driver that outputs sound from at least twosecond sound guiding holes; a controller configured to cause the atleast one acoustic driver to output sound; one or more sensorsconfigured to detect status information of a user; a power sourceassembly configured to provide electrical power to the earphone core,the one or more sensors, and the controller; and an interactive controlcomponent configured to allow an interaction between the user and theacoustic output apparatus.
 2. The acoustic output apparatus of claim 1,wherein the interactive control component comprises at least one of: abutton control module, configured to control the acoustic outputapparatus based on an instruction input by a user through buttons; avoice control module, configured to control the acoustic outputapparatus based on a voice control instruction received from the user; aposture control module, configured to control the acoustic outputapparatus based on a posture of the user; an auxiliary control module,configured to control the acoustic output apparatus based on a workingstate of the acoustic output apparatus; and an indication controlmodule, configured to indicate a working state of the acoustic outputapparatus.
 3. The acoustic output apparatus of claim 2, wherein thevoice control module comprises: a receiving unit, configured to receivethe voice control instruction from the user; a processing unit,configured to generate an instruction signal based on the voice controlinstruction; a recognition unit, configured to identify whether theinstruction signal matches a preset signal; and a control unit,configured to control the acoustic output apparatus based on theinstruction signal and a matching result.
 4. (canceled)
 5. The acousticoutput apparatus of claim 1, wherein the one or more sensors include atleast one of a locating sensor, an orientation sensor, an inertialsensor, an audio sensor, and a wireless transceiver.
 6. The acousticoutput apparatus of claim 5, wherein the one or more sensors detect apoint of interest (POI) that the user is proximate to or facing towards.7. The acoustic output apparatus of claim 1, wherein the controller isfurther configured to cause the at least one acoustic driver to outputsound based on the detected status information of the user.
 8. Theacoustic output apparatus of claim 7, wherein to cause the at least oneacoustic driver to output sound based on the detected status informationof the user, the controller is further configured to determine an audiomessage related to the POI; and cause the earphone core to replay theaudio message upon the detection of the POI by the one or more sensors.9. The acoustic output apparatus of claim 8, wherein the POI is avirtual audio marker with which the audio message is associated.
 10. Theacoustic output apparatus of claim 1, further comprising: an activenoise reduction module configured to generate, according to detectednoise, an anti-noise acoustic signal to reduce the detected noise. 11.(canceled)
 12. The acoustic output apparatus of claim 1, wherein thecontroller causes the low-frequency acoustic driver to output sound in afirst frequency range and the high-frequency acoustic driver to outputsound in a second frequency range, the second frequency range includingfrequencies higher than the first frequency range.
 13. The acousticoutput apparatus of claim 12, wherein the first frequency range and thesecond frequency range at least in part overlap.
 14. The acoustic outputapparatus of claim 12, further comprising: an electronic frequencydivision module configured to decompose a source signal into alow-frequency signal corresponding to the first frequency range and ahigh-frequency signal corresponding to the second frequency range,wherein the low-frequency signal drives the low-frequency acousticdriver to generate sound, and the high-frequency signal drives thehigh-frequency acoustic driver to generate sound.
 15. The acousticoutput apparatus of claim 1, wherein the low-frequency acoustic driverand the at least two first sound guiding holes form a first acousticroute, the high-frequency acoustic driver and the at least two secondsound guiding holes form a second acoustic route, and the first acousticroute and the second acoustic route have different frequency selectioncharacteristics.
 16. The acoustic output apparatus of claim 1, whereinthere is a first distance between the two first sound guiding holes anda second distance between the two second sound guiding holes, the firstdistance being larger than the second distance.
 17. The acoustic outputapparatus of claim 1, further comprising: a supporting structureconfigured to carry the low-frequency acoustic driver and thehigh-frequency acoustic driver and position the at least two first soundguiding holes and the at least two second sound guiding holes away froma position of the user's ears.
 18. The acoustic output apparatus ofclaim 17, wherein the at least two first sound guiding holes and the atleast two second sound guiding holes are disposed on the supportingstructure.
 19. The acoustic output apparatus of claim 1, wherein soundoutput from the at least two first sound guiding holes has reversedphases.
 20. The acoustic output apparatus of claim 1, further comprisinga flexible circuit board configured to connect at least the earphonecore and the power source assembly, wherein the flexible circuit boardcomprises: one or more bonding pads configured to connect one or morecomponents of the acoustic output apparatus or other bonding pads; orone or more leads configured to connect the one or more components ofthe acoustic output apparatus with at least one bonding pad.
 21. Theacoustic output apparatus of claim 1, wherein the power source assemblyincludes a body region and a sealing region, a thickness of the bodyregion being greater than a thickness of the sealing region, a sidesurface of the sealing region and a side surface of the body regionhaving a shape of a stair.